George, from my research I found that Blacks served on the front lines or with the armies in the field in several categories:
Body servants of the officers who brought them from home- John S. Mosby brought Aaron Burton, who served in a non-combatant function, although he was with Mosby on many occasions. While not listed on regimental rosters, they are mentioned by name in some of those officers letters. They also often attended to their wounded officers.
Blacks also served with the army as teamsters for the supply wagons and marched and rode behind the armies when they were no the move. Their names are not listed on army rosters.
At Centreville, Va., free-Blacks, Black convicts, and slaves impressed from local plantations worked on the Centreville Military Railroad, the fortifications there, and the military roadways. They came from Richmond, and one work group was referred to as being composed of 2 regiments (not fighting regiments). I have never seen a list of names for these workers.
Slaves and free-Blacks who either fought for, or attempted to fight for the Confederacy. Along with re0unions, I would check newspapers of camp meetings after the war for their names. Genealogies for Black families are also showing family members who served in the Confederate armies. The 1866 census and slave narratives for Alabama counties may list some names.