Don't hold me to time and place but I do recall the "Feelin' for a furlough" admission. This may have come from Bell Irvin Wiley's Life of Johnny Reb which I looked through again and found this...
"A less frequent resort to avoid service was the self infliction of an injury of some sort. One Reb shot himself in the foot, and another in the hand, to escape servie. A louisianian amputated some of his fingers. A South Carolinian secured sick leave by making his arm sore, and extended his sojourn in the infirmary by tampering with the wound. Another South Carolinian managed to keep himself hospitalized for the greater part of the war by aggravating the infection of a toe.
But physical disabling was a serious business. A much more common ruse to evade service was that of getting detailed to some softer assignment than soldiering..."
This is from the chapter titled "trials of the soul" and is found on page 141 of my edition.
Don't hold me to the feelin for a furlough comment being Bell Wiley's writing. My memory is pretty poor. Anyway, it seems less likely to me that this would happen then than in modern warfare (20th century to present) because you were just as likely to die of a Serious flesh wound from a gun or knife as the hosptials of that era were known to probably kill as many as they cured. Speaking offhand that is. Maybe the Union Army was different but I would doubt it very much.
FYI... as far as I know the guy from Louisiana that cut his fingers off was no relation to me LOL!