I have not read those personal accounts that you mention, but the Official Records do not seem to confirm that the 29th Virginia was attached to Corse's brigade in Dec. 1862.
Excerpts from the Official Records offer this partial timeline and assignments:
ABINGDON, VA., December 15, 1862.
Honorable JAMES A. SEDDON, Secretary of War, C. S. A.:
SIR: I received your telegram, requiring me to send two Virginia regiments from my command to report for duty at Richmond City. Accordingly, I have ordered the Fifty-fourth and Twenty-ninth Regiments and the Twenty-seventh Battalion (dismounted) to move.....H. Marshall
Abstract from Field Return of troops commanded by Major General A. Elzey, December 20, 1862 (headquarters Richmond, Va.)
[includes 29th Virginia along with the other regiments from E. Tenn & SW Virginia that had been sent as reinforcements for the Blackwater line east of Petersburg.]
Troops in the Department of Virginia and North Carolina, commanded by Lieutenant General James Longstreet, for March 10, 1863.
Major General S. G. FRENCH'S COMMAND.
(Headquarters, Petersburg, Va.)
Brigadier-General Colston's command.
29th Virginia Regiment.