Great overview I have an April 1997 version myself. One thing I've never seen is a PST II with the PST patent numbers on it. How rare are those?
PST II with the PST patent numbers on it - just not exist
Production of PST II was started in October 1995 and has "US REG TM 1325473" on handles.
Last PST with "US PAT 4238862" on handles was produced in 1986.