No, not unless i was sure of it or he informed me of such. Once someone makes me aware of something, then i am choosing to support it lending in its celebration or declining according to my conscious.
Everyone should have that right. A specially created item for something is just that - special. Not like selling over the counter what is sold to the entire general public. If they buy whats available to everyone already made, then what they choose to do with it then is on them, and i am not a party to it.
So it follows that if a couple you suspected to be gay were customers you wouldn't outright ask them if they gay, either.