Most notably, PRODUCTION DATES have been penciled or stamped on the butt end of the heel of the neck of most guitars and basses, although there were periods when this was not consistently done (1973 to 1981, for example) or simply omitted.
Fender began producing instruments in its Ensenada, Mexico, factory in 1990.
SERIAL NUMBERS and APPROXIMATE PRODUCTION DATES 1965 to 1976 In 1982 the Vintage Series of guitars was introduced.
The vintage series used a "V" prefix in serial numbers.
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.
While there have been periods of dramatic change—such as the transition periods between the Leo Fender years and the CBS years or the transition between the CBS years and the current ownership—most models are generally feature-specific and do not change from year to year.