Brian,
There is a good chance he deserted,there was a R.T. Baines who was in Co K 29th Tex Cav who was transfered to the Infantry. June of 1863. On Dec 31,1863 a 19 year old, Robert T. Baines enlisted as a Sgt. in the 2nd Ark Cav(US) he was born in Panola Co. Texas Died at Oceanside,Ca. in 1923.For your information there was also a C.S. Baines in Co K who was also transfered to the Infantry.
Mike