Does anyone have info on United States Silver Corporation 100+ troy ounce .999 silver bars? I've seen various other 100 oz bars but not one made by US Silver. I've also see US Silver Corp ONE oz art bars. I'm thinking it's from the 70s but I'm not sure. The one I saw has a seal that looks like a coin, some fancy impressed marks around the edge, & the US Silver etc etc on the top of the bar. The bottom of the bar has a quote about silver being true wealth, etc etc, plus the top 2 corners are stamped with the actual weight. In this case it was "102.5 troy ounces actual weight". Any info would be appreciated.