Manufactured in 1951 with standard markings including the Cobra rollmark on the barrel. This revolver is listed in the factory records as a Colt Police Positive that was shipped on 25 May 1951. The factory letter confirms the current configuration and goes on to state that this revolver is an early prototype/tryout of the new lightweight revolvers and confirms the alloy cylinder. The included box is also labeled as a Police Positive Special but is correctly hand numbered to the gun and hand marked in the same white pencil on the lid with "ALUM CYL.