No mention. What about these words?:
"But contrariwise, when they saw that the gospel of the uncircumcision was committed unto me, as the gospel of the circumcision was unto Peter" (2 Cor.2:7).
I think you mean Galatians 2:7 (NASB):
But g235 ἀλλά alla
on the contrary, g5121 τοὐναντίον tounantion
seeing g3708 ὁράω horaō
that g3754 ὅτι hoti
I had been entrusted with g4100 πιστεύω pisteuō
the gospel g2098 εὐαγγέλιον euaggelion
to the uncircumcised, g203 ἀκροβυστία akrobystia
just as g2531 καθώς kathōs
Peter g4074 Πέτρος Petros
had been to the circumcised g4061 περιτομή peritomē
Note that the word gospel only shows up once. In the KJV the second occurance of the word gospel is in brackets, showing it has been added by the translators. The point is that in their ministry of proclaiming the gospel they were reaching primarily different people.
At Galatians 1 Paul speaks of the gospel which he preached to those in the churches which he founded and he says that he received that gospel from the Lord Jesus for the express purpose to preach it among the Gentiles:
"But I certify you, brethren, that the gospel which was preached of me is not after man. For I neither received it of man, neither was I taught it, but by the revelation of Jesus Christ...But when it pleased God, who separated me from my mother's womb, and called me by his grace, To reveal his Son in me, that I might preach him among the Gentiles" (Gal.1:11-12; 15-16).
We can understand that the gospel of which Paul is speaking is strictly for the Gentiles by his remarks later in the same epistle:
"And I went up by revelation, and communicated unto them that gospel which I preach among the Gentiles, but privately to them which were of reputation, lest by any means I should run, or had run, in vain" (Gal.2:2).
There is no mention of strictly for the Gentiles, only that he preached the gospel, his gospel to be more exact, among the Gentiles. After ministering to Jews, Paul ministered among the Gentiles ("we are turning to the Gentiles"). He even, though, took up a collection for the saints at Jerusalem (Romans 15).
If there were only "one" gospel then there would be absolutely no reason to specify that the gospel that he is speaking of is the one "which I preach among the Gentiles."
Again, you have an understanding here whereby you are getting tripped up. You are obsessing on your idea of two gospels, so much so that these words take on special significance to you. Paul identifies the gospel he preached among the Gentiles for his audience (the Galatian church). His concern was that the words he used were consistent with the words being used among Jews. Meaning, there is one gospel, and even if different words or approach are used we need to make sure that the same content is being communicated. Paul had this concern, which is why he went up to Jerusalem.
If the gospel he preached among the Gentiles was the same gospel which he preached among the Jews then why would he need to go to Jerusalem in order to consider its relationship to the gospel which he had preached earlier in the company of some of the Apostles (Acts 9:27-29)?
Great question. His concern was that he was not making anything up of himself, but that the truth of what he was preaching would be known to all.
Of course there would be no reason for him to do that if the gospel which he earlier preached with other apostles was the same one that he was preaching to the Gentiles.
Think on this. If you say something and then say the same thing using different words, has your meaning changed? In a big world, Paul strove for unity and common corporate understanding.
Earlier you said that Paul received a gospel at his conversion.
He accepted the truth, from Jesus and from Ananias. A little different wording than receiving a gospel, but okay. When you say "received" I think you might be speaking of unique revelation or perhaps you are confused about what Paul "received" later. There is acceptance of truth and adoption of a message to be delivered. I believe what Paul received was of God, not an invention of man.
After receiving that gospel he went immediately into Damascus (Acts 9:6-8).
But he says that after he received a gospel directly from the Lord Jesus (which he preached to those at Galatia) he went "immediately into Arabia:
"But when God, who set me apart from birth and called me by his grace, was pleased to reveal his Son in me so that I might preach him among the Gentiles, I did not consult any man, nor did I go up to Jerusalem to see those who were apostles before I was, but I went immediately into Arabia and later returned to Damascus" (Gal.1:15-17).
He received the gospel which he preached unto the Jews on the Damascus road
I'm not sure about this... you seem to be making the assumption that Paul's first revelation of the gospel was on the road to Damascus, rather than in Damascus when Ananias spoke with him. How would we know if Paul received the gospel at either time? Look to those words (Jesus and Ananias).
and then went immediately into Damascus.
Later he received another gospel for those of the uncircumcision and then he went immediately into Arabia.
Two different gospels!
That is what you want to believe. But why should I make the same conclusion that you do? I'm not denying the verses... but think on this: When Paul said "we are turning to the Gentiles" did he already know what he was "going to preach to the Gentiles"? Are you saying he was then communicating to the Jews he was speaking with that he was going to be preaching a different message?!!! Why would he be bringing them (Gentiles) the same message he was preaching (Jews) IF IT WAS DIFFERENT? You are emphasizing it was not the same... but if it was not the same, then did he LIE to these Jews?! Paul submitted himself to evaluation, that his message would be not of himself, but of God. All of this to say that how you say what you say is important... and that understanding may come more quickly when the speaker/preacher has a knowledge of what brings that understanding. To the Gentiles, it was not the law, though he spoke of the law in Gentile lands. Paul pointed out, in Romans, that the Gentiles... their thoughts are alternately accusing or else defending them, and that these are a law of sorts in and of themself. So, Paul says he was not without the law of God. But someone versed in the law would understand when he says "according to the law, such and such". See, there are different ways to communicate something, but that doesn't change the gospel. There are different ways to communicate the gospel, and we desire to have a more perfect understanding as individuals and corporately. But, there is no guarantee that we will all understand things, or have the same experience, the same way. I don't have any problem with Paul preaching his gospel among the Gentiles. That does not mean to me that he was a lone wolf preaching new doctrine and starting a new church (a "new testament" one at that), as some would suppose. And, it would not mean that people are saved by primitive gospel as well as updated gospel. No, it is the same gospel preached to different people. Salvation in Christ, whether Jew or Gentile (Romans 1:16).