I have a number 3 in 45-70 with a quarter rib added by the previous owner(s). It was silvered soldered in place. The rear sight dovetail wasn't filled and is visible under the rib. The front sight was completely removed. I got it for half it's normal value as a result. It shoots very well with cast though.
The #3 in 22 Hornet was D/T'ed for Weaver bases and retained it's sights when I got it.