So, I have recently been told buy a couple gun shops now that my fullsize USP 40 is just not a popular gun because it has the stainless top (slide). And thus dramatically reduces the value. These guys are talking only in the $300 range for a resale and mid $200s for trade! I paid almost $600 a year ago BECAUSE it was the SS upper! Are these guys for real or are they trying to dupe me out of my gun?