The Record of Events for Company C for the period are:

May/June, 1863 stationed at Fort Jackson
Jul/Aug, 1863 missing
Sep/Oct, 1863 missing
Nov/Dec, 1863 stationed at Fort McAlliser

Assuming the May/Jun muster was held the end of June, 1st week of July, it looks like they were stationed at Fort Jackson.

Old Fort Jackson is a restored 19th century fort located two miles east of Savannah on the Savannah River.

Fort McAllister located south of Savannah on the banks of the Ogeechee River

M266: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Georgia