Your wrote: "I have interpreted the "attest" signature requirement to indicate that Captain Dixon, or the officer in charge of certain details, was required to give the Federal parole officer his personal assurance that the man being paroled was who he said he was in the absence of muster roll records showing enrollment date, etc."

As I noted previously, I have only seen the "attest" by a man's Company officer has been in the case where the man cannot sign his name, such as using an 'X' "his mark"

I had not thought before that enlisted man being paroled at Vicksburg were accompanied by one of their officers along with the latest muster roll. My assumption was that Federal authorities took the word of the man being interviewed.

Looking back at the certificates of my ggrandfather's 43rd Tennessee, I only seem to find authentication of his 'X' and that of his brother's by their Company K Lieutenant. On two certificates of those from other companies, their signatures by "his mark" are not authenticated.

I am at a loss to explain. Perhaps Terry Winschel, Gordon Cotton, or Jeff Giambrone may have the answer.

Those left in hospitals and paroled after their company mates had marched out of the area would explain why no company officers were available to authenticate their service.