Is there anyune besides me that looks at every coin they recieve in change for copper pennies, mint errors or silver( if you are real lucky) I have been noticing some San Francisco mint narks on buisness strike 2020 quarters lately. I have 4. 2 from the tall grass series and 2 from the Marsh Billings Rockefeller series. Anyone know the story behind these coins. I was under the impression that The San Francisco Mint only struck proof coins and Silver Eagles on occasion. Thanks in advance