From the Calif. DMV website -
The new one I like the most:
Year of Manufacture License Plates (SB 1429, Nielsen): This law expands the Year of Manufacture (YOM) license plate program to include vehicles and license plates manufactured through 1980. This law benefits owners of vintage motor vehicles who obtain license plates from the year corresponding to the vehicle’s model-year, and wish to use those vintage plates in lieu of regular license plates. Such plates are commonly found from different sources, including relatives, garage sales, estate sales, etc. The program will include the blue and yellow license plates issued for use on California motor vehicles from 1970 until 1980.