As a general rule of thumb, serial numbers can be used to denote a year range for a particular guitar. As a broad generality V000001-V004000 denote a 1982 guitar, V004000-V010000 denote a 1983 guitar, and V010000-V016000 denotes a 1984 guitar.A few popular books state that the serial numbers re-started with V0000001 when the new Corona, Ca factory opened. If you look at my fullerton inventory, you can see that this is just a broad generality.From my experience, any serial number below V016000 denotes a guitar made at the fullerton plant (1982-1984).Of course, there are exceptions to this generalization.A possible explanation is that Fender just had a large box filled with neckplates and thus placed on guitars in a semi-random fashion.Of course, the box would not contain 10,000 neckplates but rather a couple thousand at the most.This makes it possible to place a guitar into a rather tight year range just by using serial number.
I have also come across guitars with a V012000 serial number with a 1986 neckdate.
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.