Did the cal 460/461 ever come with 15 jewels? I have looked at Ranfft and all he lists is a17 jewel version of this calibre. Before anyone asks, it looks nothing like a cal 410/411. Obviously, there may be other ebauches etc that might have been used in period that I'm not aware of.
Unfortunately I'm unable to load images at present but might be able to link to an external site later.