For better or worse, I want to upgrade from manual 11" drums to power drums.

Here is a pic of what I ordered from Advance Auto for $118 (after applying a mail order discount). This was supposed to be correct for my '70 Challenger R/T.

The booster looks like the correct one (Bendix) to me, the M/C does not

I know at least the booster should be painted black, but I am not sure about the M/C. Should I paint both the booster and M/C semi-gloss black, or just the booster?

Booster looks correct, if it an original Bendix it should say Bendix on it.
The master cylinder is an aftermarket, it may be correct in fit and function, but it isn't an OEM unit. The booster should be black, its your choice what you want to finish the master with, as it isn't an OEM unit just do what you like with it.