Well it's clearly an A-1 (no inboard MG/FF). No A-1 would be sent into combat in its war-weary state when A-4s, A-5s, A-6s were fresh off the factor and more capable in weapons packs, in performance, and overall lethality.
That's why I buy that it was a trainer. As you say, there's some serious question. I prefer NOT to leave it up to HTC to do the due diligence, because many times a skin has been proposed, suggested, planned, that has no business being in-game (all-yellow 190A5 that never existed, Orange Ta-152 that was for 1 single ferry flight, black P-38, some others).
I think, frankly, that it's up to us to do the researching and checking and sell it to a skeptical HTC. Granted my early skins were more of a "ooh, I made a skin!" type of experience, but I've improved a great deal since then and try to research my subjects thoroughly. Some others I notice do not. I think it is very much our place to criticize a choice of skin subject if it is not valid, questionable, or did nothing for the war (i.e. state-side trainer skin for a P-40E)