In most cases it's necessary to match a soldier's name to a name on the census. If you know the soldier's age, it's easier to do this.
There may not be a unit history for any Georgia State Guard organization. These weren't organized for combat purposes, as they didn't have the experience, training or arms to fight veteran Federal soldiers. These were short-term units reporting to state authorities. Charged with patrol of rear areas, State Guards were expected to arrest deserters, keep roads and bridges clear, and maintain civil order.
Members were normally not liable for regular military service due to age, profession or physical condition. As you may be able to tell from my description, these men acted as military police. The work they did was necessary but not very exciting. That's why I would be surprised if anyone wanted to write a unit history.