Not likely. The current kerfuffle over all those assault weapons from the US flowing into Mexico to help out the drug cartels sounds reasonable – until you realize that most of the weapons they have are not available in the US.
Ralph Weller has a nice piece about his time living in Mexico and seeing first hand that the gun problem isn't about American “assault weapons” but the real problem is fully automatic military weapons which are not (and can’t be) sourced from the US.
Think about it. If you wanted to get a rifle to shoot your cartel enemies, would you want a single shot AR15 smuggled across the US/Mexico border or would you just go to the blackmarket in some other country and get automatic military rifles smuggled into Mexico across its giant ocean border?