A good source of information for Cal plates :
http://www.calpl8s.com/
And a great source of perfect older plates, with a brief explanation of the state's "Year of Manufacture" plate program (which I have used for a 1953 Studebaker rod) is here:
http://www.davesclp.com/
So the fact is, depending on the year, you can get perfect black plates for your car, if'n you live in Cali.