Same here in New Zealand...although some people ignore that. It's also illegal to run a decal for a licence late - quite popular on Euro Sports cars...like Ferrari and Porsche etc.Neat! Illegal here in Ontario to repaint your own plates.
In California, my area anyway, almost anything goes. A friend with a 70 painted his black with yellow characters years ago. CHIPS Officers seem in their late 20’s running around in Hemi Chargers and not old enough to know or remember what is what on plate colors IMO.
Contact Rivas Pin-stripping (David Rivas) in Santa Ana @ 714-715-3029 or R1va5_pindtripong on Instagram. He also goes to Pomona and Long Beach. Great work, reasonable prices and super nice guy.
Sure have , restored 1953 Tn.tag for me . Right colors , knock out dings. Took about 4 weeks . Try to post pic later , not to good at that .