The Compiled Service Records of Confederate soldiers include both Confederate and Union records. In fact, in many cases, the only information available on a Confederate soldier comes from Union records. The War Department transcribed information pertaining to every individual soldier from every available document onto abstract cards. This includes muster rolls, pay records, hospital records, Union POW and parole records, etc.

The War Department clerks did a remarkable job. However, the information they transcribed came from the documents they had available to them. There are a lot of records which they did not have access to. Occasionally, these records turn up in other places -- State archives, private collections, etc. Wartime letters and diaries are a particularly valuable source of information, both to confirm or expand upon known records, and to bring out new information.

Regarding hospitals at Little Rock -- both armies maintained hospitals and used private hospitals there, the Confederates before September 10, 1863, the Union after that date. There are pretty decent Confederate hospital records from Little Rock filed in the individual Compiled Service Records. The Union hospital records are usually part of the soldier's POW records, also a part of the individual CSR.

One thing to bear in mind about the records of the 36th Arkansas -- there are no regimental records in the CSRs after February 29, 1864. So if your ancestor was wounded, or was reported as a deserter after that date, there would be no record of it, unless he was captured -- Union records are about the only available source of information after the Spring of 1864.