what color for the backs of rallye wheel?

Is it satin black? gloss black? or what. 70 cuda rallyes

Yep, satin black and if you're going for a 'factory' look, shoot the argent on the outside after doing the inside in black.

Should be a little argent overspray on the black.

It's black, but I'm not certain about the satin color. My Dart has original rallyes and they are satin, but I assumed they became that way over 38 years of use.