Hi, I dont know why the previous owner took the active pre out - it's what makes this bass stand out (plus with the eq flat, it sounds like a passive jazz anyway!)
I thought ALL 1996 models had the 50th anniversary sticker on the back of the headstock - yours may have 'come off'?
have a look at the serial numbers - 96 models start with N6**** - 97 would be N7**** etc.
Great sounding bass - fingerboard fairly wide but small, lighter body.