A question on John Riley and what is believed to be his original grave and grave marker in Vicksburg City Cemetery --

On the top line of text on the grave marker, it says,
G. A. Lone Rifels
(see http://freepages.history.rootsweb.ancestry.com/~taleese/soldiers_rest_vicksburg/texas/riley_john/riley_john.htm )

Please help me with the "G. A." Does it stand for Galveston-Austin?

Thanks.