re: Gibson acoustic. Age by headstock emblem and orange sticker inside guitar.

Historic reissue? Gibson has a few round shoulder and small-body/parlors on their website right now with older style script logos and colors/cosmetics. I've also found GC is pretty good at dating their used/vintage pieces when it comes to American flagships like Gibson, Fender and Martin. Not that it's that hard to date them, they're just good about doing it in order to get top used/vintage dollar.

Keep in mind too that an old/vintage Gibson acoustic is more than likely going to have some degree of finish checking, regardless of how babied it has been. That's the nature of old nitro finishes.