Base plates are what you start with.
New plates were made in 1945, 1947, 1951, 1956 and 1963
Metal tabs or stickers were used for the years in between the new base plates
1946 California License Plates used a 1945 base plate with a metal 46 tab

1947 California License Plates were a new base plate

1948 California License Plates used 1947 base plates with metal 48 tabs
1949 California License Plates used 1947 base plates with metal 49 tabs
1950 California License Plates used 1947 base plates with metal 50 tabs
1951 California License Plates were a new base plate

1952 California License Plates used 1951 base plates with metal 52 tabs
1953 California License Plates used 1951 base plates with metal 53 tabs
1954 California License Plates used 1951 base plates with a metal 54 tab
1955 California License Plates used 1951 base plates with a metal 55 tab
1956 California License Plates were a new base plate

1957 California License Plates used 1956 base plates with 1957 sticker
1958 California License Plates used 1956 base plates with 1958 sticker
1959 California License Plates used 1956 base plates with 1958 sticker
1960 California License Plates used 1956 base plates with 1960 sticker
1961 California License Plates used 1956 base plates with 1961 sticker
1962 California License Plates used 1956 base plates with 1962 sticker
1963 California License Plates were a new base plate

1964 California License Plates used 1963 base plates with 1964 sticker
1965 California License Plates used 1963 base plates with 1965 sticker
1966 California License Plates used 1963 base plates with 1966 sticker
1967 California License Plates used 1963 base plates with 1967 sticker
1968 California License Plates used 1963 base plates with 1968 sticker
1969 California License Plates used 1963 base plates with 1969 sticker
1970 California License Plates used 1963 base plates with 1970 sticker - Commercial only
1971 California License Plates used 1963 base plates with 1971 sticker - Commercial only
1972 California License Plates used 1963 base plates with 1972 sticker - Commercial only
Genuine DMV rules from their own website
http://www.dmv.ca.gov/pubs/vctop/d03/vc5004_1.htm Print this section and take it in with you
Model Year Date License Plates
5004.1. (a) (1) ( )1 An owner of a vehicle that is a 1969 or older model-year vehicle or the owner of a commercial vehicle or a pickup truck that is a 1972 or older model-year may, after the requirements for the registration of the vehicle are complied with and with the approval of the department, utilize license plates of this state with the date of year corresponding to the model-year date when the vehicle was manufactured, if the model-year date license plate is legible and serviceable, as determined by the department, in lieu of the license plates otherwise required by this code.(2) The department may consult with an organization of old car hobbyists in determining whether the date of year of the license plate corresponds to the model-year date when the vehicle was manufactured.
(b) A fee of forty-five dollars ($45) shall be charged for the application for the use of the special plates.
(c) In addition to the regular renewal fee for the vehicle for which the plates are authorized, the applicant for a renewal of the plates shall be charged an additional fee of ten dollars ($10). ( )2 If payment of a regular vehicle renewal fee is not required by this code, the holder of license plates with a date corresponding to the model-year may retain the plates upon payment of an annual fee of twenty dollars($20)( )3 that shall be due at the expiration of the registration year of the vehicle to which the plates were last assigned under this section.
(d) ( )4 If a person who is authorized to utilize the special license plates applies to the department for transfer of the plates to another vehicle, a transfer fee of twelve dollars ($12) shall be charged in addition to all other appropriate fees.
Amended Sec. 1, Ch. 497, Stats. 2007. Effective January 1, 2008. Operative July 1, 2009. Amended Sec. 216, Ch. 179, Stats. 2008. Effective January 1, 2009.