I suspect they were both captured at Arkansas Post, however, no POW records for either of them are recorded.
John R. Coggins, age 29, Private, Captain W. A. Taylor's Company, 2nd Regiment Texas Cavalry*, joined for duty February 14, 1862 at Lampassas, Texas by Captain Taylor for the war, recorded as absent on detached service, August 31, 1862 and on the Sept. & October, 1862 muster rolls, no further records
[He must have been dropped, discharged, taken prisoner, died, deserted, etc., from the rolls sometime after August 31, 1862 and April, 1863 as he does not appear on the next surviving muster roll of May & June 1863]
* This company subsequently became Company C, 24th Regiment Texas Cavalry**. In the latter part of 1862 it was divided, the other part forming Company L, 21st Regiment Texas Cavalry
** The 24th Regiment Texas Cavalry (also known as the 2nd Regiment Texas Lancers and as the 2nd Regiment Carter's Brigade Texas Mounted Volunteers.
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Andrew J. Coggins, age 22, Private, Captain W. A. Taylor's Company, 2nd Regiment Texas Cavalry, joined for duty February 14, 1862 at Lampassas, Texas by Captain Taylor for the war, recorded on the May & June, and August 31,1863 muster rolls, as absent, West of the Mississippi River, no further records
M323: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Texas