Kinda what I figgered.
I have to say though, if the whole civil war situation is not confirmed by thorough research to have been the original start of this beef the History Channel has no business presenting it as such. Did they even actually fight together on the battlefield?
There is absolutely no corroboration I've ever found for that part of the story. The idea that Devil Anse deserted is also rather unlikely, though not impossible - especially towards the end when many soldiers deserted. I have also not found any evidence that Randall McCoy was ever a POW, at least not for any real length of time.
The guy wearing the Union jacket that Jim Vance murdered in the show was Randall McCoy's brother, Asa Harmon McCoy. The real story there was a bit different. Who actually shot him is not known, but a group of men from the area, the "Logan Wildcats" tracked him down and killed him. They were mostly a Hatfield affiliated group, and it's quite likely that Jim Vance was involved. That said, none of the other McCoy's, including Randall, really minded that he was murdered. They all considered it an offense to the family that he'd fought for the North.