2 mils wouldn't cover much. Rust pits on a project gun are a sore spot right now. Polishing/stoning is getting old.
My limited understanding is that plating does not cover blemishes such as pits. It plates overall, so you would end up with HC pits...
I've been wrong before, but have reblued a fair amount of firearms. Never any plating tho.
Generally speaking, the finish you get idepends on the base preparation, or lac there-of.