Alan, in my opinion, I would guess the "3" was mistaken for an "8." It would not be the first time errors had cropped up in the CWS&S system. I would rank Grady Howell's sources and published data above that found in the CWS&S system,

Byond Grady, I think the final source on all things concerning the 13th Mississippi is Jess McLean who has studied the 13 for many years. His 13th work is described at

http://members.tripod.com/civil_war_13th_miss/index-2.html

You might try contacting Jess at JessMcLean2@Comcast.Net