What happens If I use MWIII Guns in Warzone?

I don't own or play MWIII, however I have used some guns (ACR, BAL-27, G36, MORS) in Warzone, and gotten them to max level. I had heard that using the guns in Warzone before using then in MWIII can bug them out and cause their camos to not be able to track in MWIII at all?

Is this true? I don't wanna know I've fucked myself over from being able to get Guilded on any of the guns i've already leveled up.

I know that the MWII guns can still get camos, I've gotten Gold on several of them, but none of the MWIII guns can because they require "Operator Kills" and not "Kills".