In his book on Cavalry and Artillery Sabers, Thillmann does discuss the J.B.A. marked sabers. Apparently they are not common, and they are thought to be American made. Some collectors feel they may have been made by Ames or Emerson and Silver, due to similarities with them. But I would agree with the above, you have an authentic enlisted man's cavalry saber that someone much later had the blade etched with Confederate motifs.