I'm with Aidan, as a tool it isn't much use and to get it into a useable state you may have to do things that will devalue it as a collectors item. If it was something that was the workhorse of a well known master craftsman then that's something else entirely and is where collecting comes in, you may wish to put it in a display cabinet on your mantelpiece rather than use to plane boards in your shop.
That said, if I stumbled across one in a car boot and could turn it into mucho spondies then I wouldn't think twice about taking the cash :twisted: