Again, nobody said anything about "irrefutable proof." We're just talking about evidence. There is one piece of weak evidence that Kirk had a prior command, and absolutely nothing
to suggest he didn't. So that tips the scales at least slightly toward "yes." Even a little evidence outweighs zero evidence -- especially when there's no way of gathering any further canonical evidence that might alter the balance.
And we are talking about something entirely fictional here, after all. It's all completely abstract, not really important in any way, and not worth getting personal over. So maybe some deep breaths are in order at this point.