This is an original Corbin mortise lock set from the lower level of the house. While the upstairs had much more decorative lock sets, the lower level was a bit more basic. We still have 8 or so original keys for these locks, and nearly every door in the home has these still functioning today. The one pictured above is in great shape with great spring tension and little to no rust. This lock set was re-purposed, so it only needed to have the striker flipped over. There is a date or marking on the inside of the lock set that reads “1864″. It is possible the locks were made then since the manufacturer, P&F Corbin Company had been in business since 1851.
A little more on the P&F Corbin Company. From Connecticut, they also produced coat and hat hooks, sash fasteners, picture nails, locks, knobs, as well as coffin trimmings. Later, their main focus was only decorative lock sets. The company went through some mergers and became the American Hardware Company. Eventually in 1989 they were bought by Black and Decker and then in 2010 by Stanley.