Hmm, I'm quickly warming up to this idea. The game is never going to have the depth of firearms some people have wanted since forever. So having different stats on instances of the same weapon, to get the same effect without the art & performance cost, is actually a compelling argument.
One thing's for sure. In the current game, if you've seen one firearm of a given quality, you've seen them all. That makes finding additional ones (which is now a more common occurrence, since firearms were made more common in general) a comparatively ho-hum experience.