You're correct to point out that none of a gyno's services are needed by a troon, but I don't think that's relevant or the question here. The troon isn't going to be mistakenly referred to a gyno, the gyno politely point out she can't be of any help, but perhaps her colleague can examine your prostate, and the troon happily leave.
The troon is going to demand gyno appointments as part of his fetish, and if he's denied them he's going to call up the Media, the ADL, and some ACLU lawyers to attack the doctor/hospital for "denying women's healthcare". So the real question is how much time & energy gynos will waste "affirming" the troon's fantasy, in order not to end up with a media storm, lawsuit, mandatory pronoun training, etc.