I do not believe that one can tie a found coin to a particular person. There were shortages of small change in the American Colonies and virtually anything round was pressed into service as a coin. A Mughal coin of Aurangzeb which could have been part of the pirate's loot: Mughal silver rupee of Aurangzeb, Surat mint, AH 1091 (AD 1680) Regnal year 24 Silver, 24 mm, 11.49 gm, Krause KM 300.86