If the gun remains in pristine condition, truly looks new, I don't mind if a few rounds have gone down the tube. I also don't mind a turn line on a Smith.
I also don't get too twisted up if the box and docs are absent. It's all about the condition of the gun.
That said, I've seen guns at gun shops, which I knew for a fact were ordered in by the dealer, directly from his distributor, for his new inventory, which had gone through so much handling after they arrived, that they had picked up all sorts of marks. NIB guns that I wanted nothing to do with.
One exception: A very well priced Colt NF .45 which was perfect aside from a scratch on the ejector tube. $20 for a new one, corrected that issue.