Yeah. No. Not gonna happen. One bonus per weapon, and I'm probably going to want to hear a damn good explanation as to why you have more than one of these. (The obvious answer is, of course, a matching pair of the same sort of gun, which I'm more likely to okay. Don't try to tell me you have a Signature Hellharrower, though.)
Also remember that it isn't a bonus for any ol' Glock 19. It's your special, lucky, custom-build Glock 19 that was a birthday present from your sweet Aunt Petunia. Any other Glock 19 is just a gun.