Just for the record, these are all free blacks or is it free and slave?
we have discussed this exact question repeatedly on these WBTS threads. (the FIRST time you asked it, it was a halfway intelligent question; every time since that you've asked it, has made you look progressively LESS smart.)
the Blacks, who "wore the gray" & which H.C. Blackerby counts, were FREEMEN as ONLY free-persons COULD take The Oath of Enlistment.
there were MANY slaves who were "rented out" to the various southern states/units, by their owners, (even some NORTHERN slave-owners rented slaves to the CSA! ===> you DAMNyankees don't want to talk about THOSE particular slave-owners, do you "Bubba", as it makes you and all the other DAMNyankees look like the LYING/SELF-righteous/arrogant HYPOCRYTES that DYs actually are.) but those slaves were NOT members of the military services.
further, it is well-known that a considerable number of slaves (i don't know how many, but Shelby Foote simply said "many") were FREED to join the CSA forces.
free dixie,sw