Almost all the guns I have ever bought have been display models.
The few times that I haven't gotten that one, I have been a jerk and made them take the one they were giving me out of the box and letting me go over it to make sure there was nothing wrong with the one they gave me from the back.
Don't forget, they are firearms. They are designed to take quite a bit of "abuse". If sitting in the display case and having some people mess around with them renders them unusable, I wouldn't want to buy it in the 1st place.
Hopefully, you will be getting it to use, not just sit and look at and it will be no where near "mint" in a few weeks anyway with some good honest wear.