Doesn't someone who is a member of RCU have powder coating capability? What do you need to do it? Doesn't Harbor Freight have the tools for sale? So many questions, so few answers.

However, hi temp spray paint also comes in black as well as silver. Don't know if glossy as well as flat though. There used to be gold and silver and other colors of polyurethane spray for alloy wheels. May not be heat resistant though. Likely ok for valve covers, like Saito gold ones on GKs. Good luck.