That's a "gilt" button. They began out of some laws in the 1790s, to ensure standards on button manufacture industry. Ie.: I guess there had been spurious low quality buttons, claiming to be a certain thickness or platings, yet were cheap knockoffs. So the govt (England?) instituted some law requiring manufacturer's to put their name or logo/motto on the back. Sometimes with "triple gilt" or "double gilt" or "London fine", or "rich orange quality", blah blah blah. So yours post dates the 1790s. The practice seems to have ended in the 1860s.
The "rich orange" is probably an 1830s to '50s era button.