I believe the scoping has to do with the files in UI_INFO.rez or w/e it's called.
I never had to change the M16 since I have a perma SG550 SE CAMO LE I got from free black key for pistol event.
Ill check into it see if I can come up with something, to be honest the scope of the G36 is blow bawls. It's off centered... I'd just use the sniper scope for all guns corndog did. (Thanks corndog :P)