Howdy,
Did your A. J. Cooper have any connections in Marion or Meriwether Counties?
There is an A. J. Cooper listed as a Pvt in Company B, 9th Regiment of the Georgia Militia according to the book "Joe Brown's Pets, the Georgia Militia 1861-1865," by Wiliam Scaife and William Bragg (listed on page 293).
According to the book Company B men were from Marion and Meriwether Counties.
Bobby