This Colt Model 1900 Long Slide was Sold to the United States Government and shipped to the General Storekeeper a the Naval Yard in Brooklyn, New York on October 29th, 1900.
The Model 1900 has a rear sight safety that would keep the hammer from falling on the firing pin when active. When the safety was disengaged the sight would sit slightly upward allowing for a proper sight picture and to allow the hammer to fall and strike the firing pin.
The left side of this pistol shows has the "USN 174" roll mark while the right side shows the serial number of 1174. A small Navy trident inspection mark is stamped on the right side trigger guard bow.