I honestly couldn't say but I'm sure that one of the more knowledgeable on here could give an opinion. Overall condition may be the best indicator. Grade of gun too, not forgetting there are lower grade guns out there that are still performing as well as the day they were sold. Not a very good answer on reflection really. I'll have a look through some books later see what turns up. It'd be nice to find out if they bought guns in or assembled and finished them, or possibly both, then it'd be down to which type the one you're looking at is.
I hate to ask as I'm hopeless with computers, but do you have any pictures ?