Hello Phillip,
Your revolver is a New Model Army which is third in line after the Beals and Elliot models. The original finish on the revolver was blue. The C and A markings on your revolver are sub-inspector marks which were put on before the revolver was shipped to the Government. Originally there was a cartouche stamped on the left grip. It may not be there now because they did get worn off on well used guns and from your pictures the grips look like they may have been refinished. The front site is the early version cone type found on the Beals and Elliot model revolvers. It was later changed to a pinched site. The revolver was shipped in August of 1863.
I hope this information helps.
Best Regards,
Bill