Uwe,
The serial number on Fenders was not inteneded to track production dates. It was simply an inventory and invoicing tool. The serial number plates were purchased in bulk, and distributed to the work benches as needed. Some workers took the plates off the back of the box, some off the front of the box. And V000X1 could be on a '57 Strat reproduction, while V000X2 could be used months later on a '62 Jazz bass. The only way to establish a good production date on a Fender is to use the neck and body dates (if there are any) stamped or written on the neck heel and the neck pocket of th body. Combine that with looking at the features, (i.e. logo, decal placement, body shape details, etc.) and the production codes on the pots.
There's a plethora of information on various websites around, and some really knowledgeable folks hanging out here and on the FDP. George Edmonston who recently joined here knows a LOT about the details of Fender's Fullerton era Vintage Series basses.
BTW, I carefully call them "Vintage Series" instead of generic "reissue". That's because FMIC did use the term "Reissue Series" for a specific series. The "Reissue Series" was made in Japan in the late '80s or early '90s. They were NOT the same as the Japanese Vintage Series however. The "Reissues Series" were essentially the same as the same era's "Standard Series" except for vintage-style hardware, yellow tinged finishes, and other cosmetic details. They had the same basswood bodies, cheap switches, crappy miniature pots, bar-magnet PUPs, etc. as the "Standard Series" instruments. They were an early and not as well done attempt at what the current "Classic Series" is. While discussing US made "reissues" may not be confusing, once one starrt to mention the Japanese "reissues" we run into the problem of confusing a Japanese Vintage Series with a Japanese Reissue Series.
jte