The 1890 pump 22's have a round stud w/ a stepped down diameter shank that fits through a hole in the end of the tang and is rivited into place from the outside. There is a countersink cut into the outside of the tang for the riviting process.
The inside portion is then milled parallel to the top tang to give a surface for the tang screw to tap into.
IIRC, there is also a cross pin through the tang and intersecting the stud to halt the stud from turning when the tang screw is turned into it.
When the outside of the tang & rivited stud are polished over,,very hard to see.
I don't recall if the '73, etc were made the same way. If I can get to the back of the pile I can check a PG tang from a '73 for you,,but it may be a while!.
