Re: Did Kirk captain any ship before Enterprise?
Very little about "Where No Man" is outright contradicted later on, interestingly enough. To the contrary, changes in uniform color are later established to be par for the course; Spock having a human ancestor and speaking of her in very restrained terms is confirmed; and there's every excuse for Kirk never to speak of his best friend again (just like he never mentions his lost loves or killed relatives).
Unlike today when it seems like so many are ready to spill their guts to practically anybody about everything after knowing them for about five minutes...particularly on television.
STAR TREK: 1964-1991