Ron --

You're correct -- this man is either younger or much older than your James G. Maddox. Since your Maddox isn't on the January 1864 roll, that should mean that he's either not in the state or already enrolled in CSA service.

As far as county or residence not being a good indicator, a researcher will be lost without having that bit of information. To put it another way, you're almost always forced to guess otherwise. Georgia counties tend to be smaller than most, so it's more common to find companies composed of men from two or three counties rather than one.