Based on the company and regimental designation being the same, it's possible the state reference is in error. It's possible this man transferred to the 21st Alabama after the 21st Louisiana was disbanded, but probably not. Do you happen to know where this man lived in 1860?

Handwritten references to other states are frequently confused with the abbreviation for Alabama. Almost every NARA set of microfilm for Alabama contains erroneous references to soldiers who really belong to units from Louisiana (La.), Florida (Fla.), Georgia (Ga.) and Virginia (Va.) which have been misfiled. I'm sure the reverse is true, also.

Misfiled records usually contain only one record for a name. Perhaps the ink or pencil on the original ledger was faint, or the clerk made a mistake transcribing the state abbreviation. In any case, I'll check the 21st Alabama record and let you know.