Golden Weapons
Golden Weapons are purely a cosmetic enhancement.

Golden Ak-47 - Complete all Assault Rifle challenges.
Golden Desert Eagle - Get to Lv.55.
Golden Dragonuv - Complete all Sniper challenges.
Golden M1014 - Complete all Shotgun challenges.
Golden M60 - Complete all LMG challenges.
Golden Mini-Uzi - Complete all SMG challenges.