That’s kinda how they do diamond cut in as much a spray paint the whole wheel one colour then lathe off the face, then clear coat it. Not sure how’d they remove powder coat from just the face as it’s sprayed on as a powder then melted/baked. Masking it up maybe but I can’t see that working. There is a big difference between painting and powder coating wheels. I’ve had my customers ask about powder coating wheels in different colours loads & loads and have spoke to loads of wheel companies and alway been told it can’t be done with powder coat. Probably a very good reason for it too.