Hi Ed,
That revolver was manufactured in September of 1864. We do not give opinions on value because the value is greatly determined by the condition of the gun. If you want to learn about Remington Army Revolvers get a copy of "Remington Army and Navy Revolvers 1861 - 1888" by Donald Ware. If you want to get values of old guns get a copy of "Flaydermans' Guide to Antique American Firearms ...and their values" by Norm Flayderman.
Regards,
Billt