No they don't, but that does not mean the association doesn't exist.
No - most of the gay men I know who were gender non-conforming as boys did not have "dysphoria". They did not imagine themselves to be girls. They were just gender non-conforming in the ways it was reacted to by adults at the time - e.g. 'he's a sensitive boy', or effeminate, camp, etc.
Only a vanishing minority of boys think or insist they are girls, unless they are encouraged by a demented society that it is possible that they could be girls.
A standard insult for gender non-conforming boys used to be 'you are a sissy'. Girls were not called sissy because that made no sense. The insult 'sissy' is an implicit acknowledgment that the person being insulted is a boy. I don't believe in insulting gender non-conforming boys. So much the less do I believe in pretending they are girls.