Bob, the emplacements are likely very real. There was action all over that part of the state, especially in 1864, during the Atlanta Campaign. This site lists battles and skirmishes in the area for that year, with lists of Union units involved. There are numerous artillery units listed. http://www.researchonline.net/gacw/battles1864.htm

Ball Ground was not incorporated until 1883, but has been settled for centuries. In the 1700s, the Cherokee and Creek tribes settled a war by playing a ball game similar to lacrosse. Kennesaw Mountain is to the south west, in neighboring Cobb County, my home, where Sherman made a bad decision in late June to attack Confedrates dug in on the mountain. It cost him about 3,000 men. It is feasible thre were Confedrate units in the Ball Ground area at that time. Stan