Shooting clear on aluninum

OEM aluminum parts like wheels are usually anodized, not painted with a clear coat.

All of the clear coats that I'm aware of are intended to be a final coat over paint, so using them over bare metal usually results in adhesion problems. Not saying it's impossible, I clear coated a polished steel motorcycle frame once, but the results were mediocre at best.

And, weren't most of the bare metal dog dish caps stainless steel? At least the OEM ones? I know that all the bare metal dog dish caps that I have are stainless steel. The dog dish caps that weren't stainless were painted.