You’re welcome Arutha!
The pin that can wear out or shear off that I mentioned is on the winding piece that you remove from the winder. That pin catches the hole in the inner coil. After catching that hole you would turn that same piece to wind the spring into the winder. If that pin is worn short it will be difficult to catch the hole. A new pin can probably be inserted without too much trouble but might as well get a good one to start with.
Good luck on the bidding if you decide to get that one Arutha, If it gets away from you I’m sure you’ll find more like it. It’s a fairly common winder.