Intake/Exhaust Manifold

[Jazzjr]

I acquired a Exhaust Manifold without any Pits on it, best I have ever found, the Intake had a carb mounting ear broken off, so I'm using another Intake. While I have them split, I sandblasted them, the Exhaust I sprayed with Eastwood Stainless Exhaust Coating and Ford Model A Green for the Intake.

My Question is, before I Mount them together, should the Flat Mounting Surfaces of both be Free of Paint and just Bare Metal ??
I believe the Exhaust pre-heats the Intake, and would be better if left Bare metal to metal. Have searched for an answer, but have come up empty handed.
After I bolt it together, I will have it Planed