Thanks for the pictures.I remember seeing these when I worked for DGW in the very HOT summer of 1958.
Bob Roller
Once upon a time I did a modification on one of these and it was an improvement.I removed the hammer screw and the hammer.and
found the diameter of that screw hole BEFORE it was threaded and then using that hole I cross drilled it all the way thru the bridle and
then made a screw with the threads under the head and a smooth shank to create a tumbler support bearing shaft.Using the larger size
of the tumbler shank thru the plate is a bad idea and once the modification was made and a drop of oil applied it felt like a different lock.
This was done for a local man and the lock was still assembled when this was done along with a rehardened frizzen.
Bob Roller