Dating a fender p bass
CBS-Fender used this neck code system concurrently with the standard Month-Year date stamp that had been in use since 1962.Both type of stamps can be found on Fenders made from 1969 through 1971.The new code consisted of 6, 7 or 8 digits and was usually stamped in green ink.
First, the chances of having an intact stamped code is about 50-50.
Breaking up the code we get: 5 = code for Precision Bass 291 = batch or lot code? Break it into pieces: 22 = code for Stratocaster 384 = batch or lot code?
2 = February 9 = 1969 B = 1 5/8 inch neck width (correct for a ’69 P-Bass). 10 = October 9 = 1969 B = 1 5/8 inch neck width Exceptions do exist.
Andre Duchossoir briefly discussed his findings for the 1972-80 codes in his excellent Telecaster and Stratocaster books. I used this information as the starting point for my research.
I examined and/or received information regarding stamped codes for about 150 Fenders made between 19. In most cases, the stamp was smudged beyond legibility or the stamps were incomplete. Some guitars simply had the model name, such as "MUSTANG" stamped on the butt end of the neck in green or red ink.