I don't know if anybody watches Pawn Stars on the History channel. Last nights episode featured Vic Flick selling his '61 strat which was all original, but has had a re-fret. He provided documented evidence of the hits that he played on it. The funny thing was that, the owner of the shop didn't really know who Vic was but when he called in an expert, all was revealed. The guitar changed hands for $55,000 with a valuation of between $60 - 70,000.
I know back in '94 or '96 when Bruce was interviewed by Guitarist, he said if anyone wanted it, they could start at £250,000, I'm not sure if he had been taking anything.
Again going back to Pawn Stars, a number of months back the nephew of Mary Ford (the wife of Les Paul) sold her original white Les Paul guitar (SG shaped) and he got $75,000.
So, as in all things, the value will be determined by what someone is prepared to pay for it.