Jim, you are probably right about the 20 being a grade 10. There is a 20 stamped at the front end of the lock plate with an X above it, I just never connected it with the grade. The 12ga also has something stamped there but is illegible. Interesting also is the # stamped in front of the hammers on both guns, it is a 4 digit # that has nothing to do with the serial #. It is repeated on the gun in several places, must be a job # or such. Another thing I noticed is that both guns serial # is prefixed with AM ???
Jim
