These books are the same resources we refer to here at Fender, when trying to research answers to these same history and dating questions.
In March 1985, CBS sold Fender to a group of private investors.
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.
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.