Condition is everything in regard to resale value in IMHO... Some of the pictures on the back of the bass appear to be either reflections and maybe some scratches, so it's hard to value without knowing for sure what they are.
When you look at the bass, are there any noticeable dings, scratches that are obvious, etc?
I like to say that having precedence for what others pay is a good way to gauge value, but if I fall in love with the look of an instrument price is almost irrelevant (within reason).
The Cocobolo top is considered a top quality top (highest priced option for tops if memory serves), that appears to be the only real upgrade from what I can see. It's a pretty bass no question, the figuring is really nice!
It's going on 29 years old, so the condition of the neck (can it be set up and play cleanly across the entire neck without the action being super high, fret ware, etc) is a question mark - pictures and maybe taking it to get set up could help you know for sure.
If this thing was in Excellent condition, meaning the neck played right and it didn't have any huge nicks or dings I'd probably pay somewhere in the area of $5K for it - maybe more if I really connected with it.
My recommendation is do some research on Reverb, look at what others are listed for and look under the sold filter to see what others have sold for (or at least what they sold for based on what they were listed for, sometimes I've found these not to be right based on what I purchased a bass for and what they say it sold for).
HTH