The records of the prewar Arkansas State Militia have lots of holes. There are quite a few lists of officer appointments from the Mexican War period, then very spotty records until just before the Civil War, when more officer lists show up. There are perhaps a dozen or so regimental muster rolls from the early Civil War period, then practically nothing until the 1870's. There's almost nothing on the 12th Regiment, at least as far as I've been able to ascertain. No mention of Daniel C. Govan that I've found.

Anthony Rushing has some officer appointment lists from various periods in the 1800's. He might be able to shed more light on the 12th Regiment.