The compiled service records found at Fold3 show the following:

S J L Andrews private 4th La Cav
Captured near Alexandria March 20, 1864
Exchanged at Red River Landing July 22, 1864

Solomon Andrews Co I 6th La Cav

Feb 9, 1915
Respectfully returned to the President, La Board of Pension Commissioners, Baton Rouge
The Confederate records show that Solomon Andrews [name not found as S[marked through] J [L inserted] Andrews], private Co I 6th La Cav CSA enlisted Feb 19 [year not stated but evidently 1864] only roll on file he was reported present.
The Union records of prisoners of war show that one S J L Andrews, private Co __ 4th La Cav CSA was captured March 20, 1864 near Alexandria and exchanged at Red River Landing July 22, 1864.
No connection has been found between the regiments above mentioned and no later record has been found.
Signed
The Adjutant General

The 1915 letter shown above was type written and revised by hand writing to cross through the letter S and to add the letter L for the name to then read J L Andrews vs S J Andrews