Painting aluminum valve covers?

Not sure if this question belongs here but here goes. I want to paint Mopar valve covers, Mopar Performance with logo and the raised "fins" the same color as the engine. I want the fins, logo and Mopar Performance script unpainted. It seems that paint won't stick well to the polished aluminum valve covers but will the "as-cast" versions. Am I right so far? If so, the fins and writing will be flat gray but I'd like them polished. Could I polish the fins, logo, and script before painting? If so, how does one polish flat gray "as cast' aluminum? If this will work, can I paint the entire valve cover without taping off what I polished and just take the paint back off with some work after the fact? I don't have all this together yet but need to plan it out before I spend money on a bad idea. Thanks in advance.