I thank you all for your assistance in this. On the lock plate you can read out Saarn. We thought it spelled out. "Saint" but was never completed. Oh well. I would like to have this converted back to its original shape, but my father desires to keep it as is. We'll see if, in time, we can bring it back. The hammer of the rifle is unique, it had a large 'cup' configuration on the striker.
As for Saints and Palmers, I do not know when or where the families crossed. I just know, according to my father, that somewhere the Saint side of the family married into the McMillan family. What happened to the Palmers, I do not know. Unfortunately, these parts of the family have been vague and hard to understand.