I've been interested in these for a while, firstly because I fell for buying a '50th Anniversary' Precision 1996 model a while back that turned out just to be a regular 1996 American standard with a little sticker on the back of the headstock and also because I now own a proper 60th Anniversary Precision bass.
It's easy to get confused I think as there have been commemorative models to celebrate Fender anniversaries, as well as to celebrate the history of both the Precision and the Jazz. As a result, a lot of models appear to be anniversary models when they are not (like the one I thought I'd bought) and are sold as such.
Here's what I have found out but I'm sure there's more to it. If anyone is able to add more detail to this or photos of genuine anniversary models or correct me where I am wrong then that would be great.
1996 – 50th Anniversary of Fender
Sunburst Jazz and Precision with gold hardware and commemorative neck plate
ALL OTHER standard models from 1996 had the 1996 sticker on the back of the headstock. This does not make them anniversary models.
2001 – 50th Anniversary of Precision Bass
Butterscotch Blonde model (black anodised pickguard) – commemorative neck plate
2006 – 60th Anniversary of Fender
Sunburst Jazz and Precision – commemorative neck plate AND 60th anniversary jewel and ribbon on headstock face. Special silver hardcase
ALL other standard models had the 2006 anniversary silver button on the back of the headstock. This does not make them anniversary models.
2010 – 50th Anniversary of Jazz Bass
Candy Apple Red anniversary model, rosewood fretboard, pearl blocks, matching headstock – commemorative neck plate
2011 – 60th Anniversary of Precision Bass
Blackguard Blonde Anniversary model, 51 P bass style with split coil pickup, maple neck – commemorative neck plate
All other US Standard and Special Precisions from this year had a commemorative neck plate. This does not make them anniversary models.