There were periods of time when this was not consistently done, (between 19), and there are certainly other examples of short periods of time, and individual pieces, where the dating was simply omitted.
Neck dating is useful in determining the age of a guitar, but is not definite.
instrument production history, production dates have been applied to various components.
Production dates have been penciled or stamped on the butt end of the heel of the neck of most guitars and basses.
A Z0 prefix dates to 2000, a Z1 prefix dates to 2001 etcetera.The serial numbers do not immediately reflect the change, as CBS continued to make instruments using existing, tooling, parts, and serial number schemes.The following chart details the Fender serial number schemes used from 1965 to 1976.They were stamped on the back vibrato cover plate (early '50s Strats), and on the bridge plate between the pickup and the saddles on some Telecasters.But due to the modular nature of Fender's production methods, and the fact that most serial numbers schemes are not sequential and usually overlap from between 2 to 4 years, (from the early days of Fender, through to the mid 1980s), dating by the serial number is not an exact science.