No dealer or gun shop that that I've ever seen, here or abroad, stores their guns butt up. Maybe some do, but I've never seen one.
That's like saying: "I've never seen a Used Car Lot that stores their used cars inside"..........Collector car stores keep their vehicles inside BTW......
To a gun shop/dealer guns are ONLY sale items waiting to earn revenue, not their personal collection....what do they care, handling marks everywhere, finger prints everywhere etc.....they sure don't shoot them regularly and clean them regularly either, do they.........?........