I have five model 51050 folding guards that I am giving a few of to my son I bought three from Parker and they have word Case in the bomb inlay Tested 19USa on the front and 51050SAB on the back under TestedXX and two I bought from a local dealer in the 1990s that have case in a circle and 51050 LSSP on the back, and CaseXX SS USA on the front. Any info on these would be great! Since I am a Gold member some idea of value would be great too!