Very possible. While no major battles were fought in or around Athens, the town was occupied by both Confederate & Union forces because of the railroad. Like other East Tennesseans, locals were divided in their loyalties, which resulted in hostilities between family members & friends that lasted for years in some cases. Many Athenians fought for both North and South. Economically the town suffered tremendously.Due to the way the letters are offset I am thinking it reads:
T N
ATHENS
It could be a commemorative notation by a Union soldier captured it near Athens TN, although I am unaware of any major battles or skirmishes in that area.