George,
Thanks for looking into this and replying.
The information from the above source also mentions: Roster: Sumter County, GA
Captain George A. Brown
1st Lt. David A. Mayo - Wounded left leg at Griswoldville
Sgt. W.H.D. Cook - Wounded in mouth at Griswoldville
Sgt. Charles W. Morgan - Killed at Griswoldville

When looking these officers up at the nps site they show up in the 4th Regiment, Georgia Infantry. Was this regiment reformed as the 11th or visa versa?
Thanks,
Dan Hill