He was an inspector for the US Army. This was probably the one that stamped this cartridge box. The item "Very RARE CIVIL WAR Stamp A. Photo of Cartridge box Stamped" is in sale since Sunday, January 17, 2021.
This item is in the category "Collectibles\Militaria\Civil War (1861-65)\Original Period Items\Other Civil War Original Items". The seller is "cwcollectr" and is located in Staten Island, New York. This item can be shipped to United States.