Have you seen these two documents which are located at the U. S. Army, Military History Institute, Carlisle Barracks, Pa?

USAMHI
RefBranch
laf Dec 99

12th Mississippi Infantry Regiment

Giles, S.H. War Years C.S.A.: 12th Mississippi Regiment, Major…, Q.M. Original Letters, 1860-1865. [Ed. By Shepherd Spencer Neville Brown, Sr.] Hillsboro, TX: Hill Coll Pr, 1998. 479 p. E568.5.12th.G54.

Love, William A. "Mississippi at Gettysburg." Publications of the Mississippi Historical Society, In Gettysburg Sources, Vol. 1. Baltimore: Butternut & Blue, 1986. pp. 122 49 (14 photocopied pages). E475.53G47.1986v1.