Neck-dating can be useful in determining the was produced, rather than the complete instrument.
Given the modular nature of Fender production techniques, an individual neck may have been produced in a given year, then stored for a period of time before being paired with a body to create a complete guitar, perhaps, for example, in the following year.
The Japanese-made Fenders do have some slight serial number differences (typically a "J" serial number prefix). I believe this was a mistake on Fender's part using the same prefix for both U. Below are some examples of letter prefixes used in recent serial number schemes.
Japanese Serial Numbers on Peghead Decal Note the lack of S, E, N series.
I had just gotten home from a cross-country ferry of KW's from Fort Hood, Texas to Roswell, New Mexico. By entering this site you declare you read and agreed to its Terms, Rules & Privacy and you understand that your use of the site's content is made at your own risk and responsibility.
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.
I provided a valuation in that case, in the other thread.
Just wanted to ensure I had the correct serial number before responding with the date and value of the guitar.