I was going to buy an acoustic, but I noticed an uneven yellowish tint on its binding. Is it all right? I heard, that such tint appears only on older guitars. But this guitar is new with all the labels intact. Is it ok to buy such guitar or there is a quality problem? Thank you very much!
Which guitar?

I've seen Martin guitars where the stain or wood pigments have run into the nitro finish, and it shows against the white binding. It looked off, but reflected poor design rather than potentially poor performance.

I would likely try arguing for a substantial discount, on the grounds that it is blemished.