All reasonable evidence indicates that he was. He was indisputably born in anglo-saxon society, which means either North America or in the British empire. In his early life he was either the slave or servant of an Englishman by birth and his North Carolinian wife and at the time of his joining the Shenandoah's crew he was working for that same Englishman, who was by then a confederate soldier. That would make him in the employment of a confederate as of 1864 and thus in all likelihood a confederate himself prior to his service on a CSA warship.
As for your claims, no evidence whatsoever exists to support your earlier speculation that he was African or Jamaican. As a matter of fact, the Liverpool Mercury reported that almost all of the ship's crew contained self-identified southerners. The next largest ethnic group they reported, at least by accent, was Scottish.