I have 3 bars from 1968, two are true grease bars at 100.4 toz but the 3rd is 250toz and stamped SS.548 on a short side. I'm baffled by the stamp. I had 6 coin shops look at it and with all the knowledge no one can answer what it stands for.
I am told that the all grease bars were made from coin silver and an average of 90%.
any thoughts on the marked bar......