Not so fast, Jamie. We had at least one other set of twins. Found out about them after researching the Hugh McLaurin Letters.He was in Co. E "Franklin Beauregards" as were they. These may not be the only twins, but are the only ones I could remember.
From the "Lest We Forget" Roster:

"Webb, Alexander Hamilton “Ham”. Pvt. became 1st Sgt. WIA Ezra Church and leg amputated at Atlanta, later died. [son of Kinchen Richard WEBB Jr., Capt. Co. D 33rd Miss. Inf. and Margaret P. MAGEE. His father was a farmer in 1850 in Amite County, Mississippi. He appeared on the census in 1850 in Amite County, Mississippi.-rjs] (See also Alexander C Soldiers and Sailors)[“Died Aug. 4, 1864 after right thigh primary amputation July 28, 1862-Medical and Surgical records of the Civil War, Index !, Vol. XI, P. 271.] [Twin brother of John L. Webb; Their sister Mary Jane married Julius T. Havis, Co. E. See also John W. F. Webb]

Webb, John W. F. Pvt. not mustered in the 7th Miss.; joined Co B 14th Conf. Cav. [son of Kinchen Richard WEBB Jr. (Capt. Co. D 33rd Miss. Inf.) and Margaret P. MAGEE. His father was a farmer in 1850 in Amite County, Mississippi. He appeared on the census in 1850 in Amite County, Mississippi. Twin brother of Alexander Hamilton Webb, Co. E; Their sister Mary Jane married Julius T. Havis, Co. E; See also John L. Webb-rjs]"