The records of being killed in action at Battery Wagner and Fort Johnson refer to the same event, same place and same soldier. The famous assault on Battery Wagner depicted in film took place on July 18th. It's possible that this man was a conscript from Dade County, but that's just speculation on my part. If his widow never remarried and lived in a Southern state after the war, she could have applied for pension support. Have you checked? A statement as to his Confederate unit would have been required as verification of service.