Yes, was watching this too.
Okay, here goes: finding a figure like this with the unpainted area is not that rare, unusual but not rare. Having said that, it is Boba Fett and there are loads of collectors who will want it.
The key to this figure is the orange area on the leg - I really want to say this is discoloration. It happens on figures of this age and sometimes the effects are really weird but I'm not so sure on this figure, it does look like the paint. never seen one with this kind of pain application before.
If it is straightforward discoloration then you're looking at anything between £50-£100. If that is paint then who knows, a Fett collector might go even more than that.