Non-reverse Thunderbird body with a jazz bass neck, how much?

I may have the chance to buy one of these and was wondering if anybody could help me out with how much it should be worth? I am a huge fan Entwistle who is the only person I've ever seen with a similar bass. And I freaking love it.

Now, I don't have all of the details yet and I realize there can be a huge number of variables. But can anybody help me with how much, ballpark, I can expect to offer so that neither myself nor the seller get screwed over?

 

I'm gonna try, been looking for this exact same thing for a while!

 

I know there isn't much info there at all. I am waiting on the details. The little bit of research I have TRIED seems to go along with @godofthunder59 's thoughts. I don't know a whole lot about older Gibson stuff. Fender, yes. Gibson, very limited. And I don't know the details yet. Basically the owner has passed away and I am a friend of a friend of his friend. I'm not pushing because I don't want to be a douche about it. If I don't get it, I don't get it. I want it, but not at the expense of being inconsiderate or pushy during someone else's loss. Will definitely post more info once I get it.

 

You were right. Hit the nail on the head with everything. My buddy took it apart and looked at it. All 60s and 70s electronics and hardware. 60s chopped up third and I don't know why none of us were able to read the headstock (Precision) but it is a 70s precision neck and headstock. Unfortunately, I was 2nd in line and our mutual friend picked it up for 1500.00 CAD. DANG!!!!!!

 

Yeah, the parts are worth way more than the bass itself. Oh well!

 

Yeah, I wanted it pretty badly.