I was going to post this in the other thread about this lock, but thought would be better here.
The most likely way for the current configuration of this lock is that these components are not all original to the lock plate. Nor is the lock plate original to the rifle.
From what I see, the lock was originally a flintlock, as was the rifle. At some point both were converted to percussion. Then again, both were converted back to flintlock. However, I'm not certain that lock and gun actually came down through time together. One reason, in the next to last picture of the rifle, the lock plate looks to be a good bit too short for the inlet mortice. Not the end of the world, as lots of these guns have replacement locks in them. Some were time of use, others, more recent additions. Actually, lot's of these guns have come down through time with their locks missing.
As for a guess of events, at some point, likely in time of use in some other rifle, the lock was converted to percussion. Maybe the tumbler was broken or missing, or maybe the owner didn't want a half cock notch and the percussion tumbler was installed.
Down the road, at some point this lock and rifle ended up joined. Probably, in the not too distant past, the then owner decided to have it converted back to flint. The job was done, but left many signs of that work being done.
Please don't take this as criticism of your lock or rifle, because it isn't. Lot's of these old guns and locks have gone through several configurations in years past. This is just a simple and reasonable way for a flint rifle to be found with a percussion tumbler in the lock.
John
