To find what some stuff has actually sold for go into ebay, on the right of the box that says search it says advanced, click on that and an advanced search comes up.
Then enter the item your looking for and down a bit is three boxes... Title and listing, completed listings and sold listings.
If you tick the box that says sold listings and then click on search a list of stuff of your keyword search comes up.
The amount in green is what it sold for.
If you tick the box that says completed listings and then click on search a list of stuff of your keyword search comes up. The amount in green is what it sold for and the amount in black was the asking price that did`nt sell.

I can`t find out the amount of those best offer accepted though....

Just my opinion but for a WB in good nick with factory 253, 4 speed, GTS dash and bucket seats I`d be staying put at $15k. Different story if you had to get rid of one I guess.
I know of two such vehicles where the owner has them parked in the shed and not willing to part with it.