Treyarch’s David Vonderhaar has revealed that Black Ops 2′s weapons will have their own prestige, separate from your characters prestige. You can only prestige a weapon up-to two times, though.
As we already know, when you prestige in Black Ops 2 you don’t lose any of your weapons unlocks or the weapons level. The same goes for when you prestige a weapon in Black Ops 2. When asked “if weapon XP converts to next prestige, will you have to prestige your weapon or will it go back down to 0 or stay at max?”, Vonderhaar replied: ”Stays where we [sic] it was. Weapon level and weapon prestige level totally independent of your level. Not reset by level prestige.”
So, not only can you prestige when you hit level 55 in Black Ops 2, but now you can prestige your weapons, too.