Definitely will be a red.

There is a process called electroforming that deposits a copper "strike" followed by a finish plate or nickel strike followed by chrome onto nonconductive parts. I'm not sure that it would hold up to repeated use however. I've experimented with the process a little by gold plating a pine cone, but the results were only marginal. In short, it's probably not a good idea to plate plastic for this application. You can probably get a jeweler to cast some solid metal buttons and knobs for you if you really want them.

Stu