Circle I is Owens-Illinois Glass Company, located in Perrysburg, Ohio. Approximately 25 glass manufacturing locations in the US and Canada. Finding a bottle from Owens-Illinois is not uncommon, more so than Kerr Glass Manufacturing Corporation, who only operated 7 glass plants by 1975 (I think mostly East coast). So it's probably not surprising that you would get a bottle from Owens-Illinois (Ohio based) and I would get a bottle from Kerr Glass Manufacturing Corporation (East coast based). Whatever beer brand we're searching for, they were large enough to purchase bottles from 2 different glass companies, and were probably well distributed across the US. I hope it's not some Budweiser collectors edition or something boring like that! But my bet would be that it is a US based company.