The following chart details the Fender serial number schemes used from 1950 to 1964. 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. Most notably, production dates have been penciled or stamped on the butt end of the heel of the neck of most guitars and basses.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 once again, 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. MADE FENDER STRINGED INSTRUMENT For the majority of Fender's U. instrument production history, production dates have been applied to various components.While this neck dating is useful in roughly determining the age of a guitar, it is certainly not definitive.
So, obviously a neck date, while being helpful in providing a date range of production, it cannot be a definitive reference.
Unlike the auto industry which has specific model years for their products, most specifications for a given Fender instrument model, change little if any, through the lifetime of the model.