These plates were from the 1960's and from Harold Hess in Livonia Michigan.Hammers also and there was a low end mechanism copied from the same lock.I still have one,An antique lock was used to make those moulds and the project started in Texas by? :-\Curt Pearson.
Just for hoots and giggles I made ONE with a 3 pin English mechanism.The moulds for this lock and many others were for years in the shop of Jerry Devaudreuil in Wooster,Ohio and after he passed away,Log Cabin Shop in Lodi,Ohio bought his moulds and remaining inventory.Liza Kindig told me she bought all of these moulds and parts so they would escape being taken to a land fill by someone who has/had no idea about what these items were.The earlier mentioned Harold Hess operated as International Arms and got a visit from the BATF because of his choice of business name. One of the Federal men became a friend and I made a number of flintlocks for him and he had Len Meadows at Shady Spring WVa make some nice guns.Jerry Devaudreuil also used "International Arms as an identifier but no visits from the "Feds".
One last thing,whoever made that rifle has a good idea about inletting the breech/lock area.
Bob Roller