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.Vintage 1963 Gibson Melody maker double cutaway sunburst finish with checking overall,factory option maestro vibrato .Most MM by 63 were finished in cherry ,the vibrato is a factory add on extra option offered by Gibson.Vintage guitars ,players guitars cool affordable,rare,vintage and collectible guitar and gear sales,the obscure and under appreciated guitars.Vintage fender guitars,vintage Gibson guitars, Vintage Ibanez guitars, Guild guitars, Valley arts guitars, Gretsch guitars, Taylor guitars, Martin guitars, Takamine guitars, Stratocasters , Telecasters,guitar cases,and guitar parts.
Given the modular nature of Fender's production techniques, an individual neck may have been produced in a given year, placed in the manufacturing warehouse and remained in stock for a period of time, and then subsequently paired with a body to create a complete guitar in the following year.
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.
While this neck dating is useful in roughly determining the age of a guitar, it is certainly not definitive.
They just grabbed whatever part or component was ready and put together the instrument to fill an order as fast as possible.
The general rule of thumb is that a bass is as old as it's newest part, or at least it's latest dated part.