window regulator question

It won't roll down, seems like it is stuck solid. The previous owner (a bodyman) said it needed to be replaced but he could never find one. I haven't taken off the panel to check it out myself, maybe I should before buying. I 'm laid up for a while and didn't want this one to get away if this stuff is hard to come by as I 'm thinking.
Bob

I work at an auto glass center and we usually repair old regulators instead of finding another one. I would definitely get it out if you dont drive the car everyday. It might be just something simple.