That bass is an '86 Series II... it's been for sale a few times, most recently twice in the Nashville 'burbs.
I am not sure on the exact timeline for the extended upper-horn body, but the mid-80's are dotted with these. They seem to phase out about the time we start seeing Series electronics show up in different shaped basses. I can't remember seeing many from the 90's. The long-horn design, I'm fairly sure, was to counter the inherent balance issue with long-scale Series basses. Works out well too... one of my Distillates, the '85 fretless, has a variation on this design.
