Thank you very much clearing up the confusing i had about his date of promotion. Would you happen to know name of the soldier who preceded John McGee as Junior 2nd Lieutenant? And you mentioned that McGee was elected several weeks before becoming Jr 2nd Lt.; do you know the exact date of his election?
My ancestor is also listed in casualty lists from the "Southern Confederacy" for the year 1862; he is listed as:
Bvt 2nd Lt John McGee, Co. B., w. slightly in breast at Fredericksburg [Southern Confederacy 12/30/62]. Is the term "Brevet" the same as "Junior"?

Best regards!
John D. Kotila