There is a possibility at least one of them wore a 'Columbus Depot' jacket.
scroll down to near the bottom of the page..
http://www.geocities.com/Pentagon/Quarters/1864/cd/cdjacket.htm
I also had ancestors in that unit...Cowan's Battery.
Located at the Confederate Memorial Museum in New Orleans is the regimental flag of Cowan's Battery. It's a Van Dorn pattern flag.