This is true. Forest told several of his black servants that if they would go with him, he would free them when the war ended.
The question is, did these men serve as soldiers in his cavalry unit or attend to him personally. that is, take care of his camp, tend to his horses, run messages for him.
That is a fact that is, un-proven, to this day, at least to my satisfaction.
They were supposed his personal bodyguard as well as, cooks, musicians, etc.
The article I read said they were actual cavalry. I am thinking now that I should have bookmarked it.