The big difference between the Military and Civvie 1851 pistols were the Civilian models were tarted up with silver plate on parts of the backstrap and trigger guard. They also had options for hand engraving, etc. for a price.
The price of an 1851 was between $20.00 and $40.00 at the time.
Lots of good information available for Colts, using the serial number for reference.
Strange how he kept enrolling and then being relieved after a few months. Perhaps the militias went in and out of service depending on the proximity of enemy troops.
Also struck me that it does not seem to have occurred to anyone that the gun could have been a battlefield pickup by Jacob Cogdill. There must have been lots of guns laying around after major battles.
cheers mooncoon