Sam, as Michael said the 2-digit prefix on the CHP unit numbers are not necessarily year-specific. I have seen 38
xxxx plates on at least two different model year cars (I haven't had my morning coffee yet, so I forget which years). As a result, I have also seen two cars from the same year having different 2-digit prefixes.
Here is a somewhat related post on the CHP forum -
http://www.chpforums.com/forum/showt...399#post104399