I used to know the different patents in my head, that was then. If you go here you can see what all the patents are that were applied to L.C. Smiths. http://www.lcsmith.org/history/patents.html
If you are like me, I have to take each and every one apart and look, but taking the lock off is easy and on the left lock plate on the inside you should see November 27, 1883 stamped in there.
Just make certain when you put that lock back on that you push the rear trigger forward so that the trigger plate is lowered so that the sear fits or else you will bind the sear against the trigger plate. (not a big deal to do)