As far as I know there is only one "classic" plate for 20 years and older. Up to 2014 DMV was issuing "early american" plates but they switched over to the classic plate. Other than a statute authorizing DMV to issue the plate and a property tax value limit of 500 dollars on the vehicle registered as such there isnt much other info to find on it. The classic car collectors lobbied a few years ago and got their way. Whatever statute restrictions there were, was wiped off the books.