The shop I go to deals with so many used guns that most guns you can buy new chances are there's a used one sitting in one of the cases. They have designated display models for newer pistols that just hit the market because alot of the times those sellout so quick they wont always have them in stock, but they still want people to be able to handle one in case they want to put in an order. Anytime I have bought new from them they go in the back room and pick out a NIB pistol.
They way I see it, shops should sell display models for slightly less even if it's never been fired. They buy the guns a dealer prices anyways, so even if they break even on the gun it served it's purpose and they got their moneys worth in my opinion. It's like going to sears and buying the floor model for a grill or exercise machine. It saw a little use so it's sold for a little less.