Alan,
Yes, I have looked at both histories and then read the letter again. There is a whole lot that don't jive. I recommend that he takes the "letter" to a document specialist.
Respectfully,
Gerald D. Hodge, Jr.
War Between the States Historian
Historian: 39th Georgia Volunteer Infantry Regiment
http://39thgavolinfrgt.homestead.com/39thHomepage.html