Manufactured in early 1943, this is an outstanding example of an extremely early production Ithaca Model 1911A1 pistol, one of only an estimated few hundred at the very start of production which received an "I" prefixed serial number. These pistols are discussed on p. 108 of "U.S. Military Automatic Pistols 1920-1945" by Meadows, and serial number I-856531, only ten digits away from this example, is pictured on p. 106 and 108. It is theorized in the book that the earliest Ithaca manufactured pistols received the "I" prefix in imitation of the Singer produced pistols, which all received an "S" prefixed serial number. The "I" prefix appears to have been dropped shortly after production began when Ithaca was notified by the Ordnance Department that it was unnecessary, making these "I" series pistols incredibly rare on the collectors market. This early production pistol also has the desirable Dulite finish, which is only seen on Ithaca manufactured pistols until around the 880,000 serial number range, when they switched to the more standard phosphate-based parkerization. The left side of the slide is marked with the standard two-line Ithaca Gun Co. address, and there is a "P" proof on the top rear. The left side of the frame has the "FJA" inspection mark and "P" proof below the magazine catch. The right side of the frame has a crossed-cannons ordnance proof at the rear, U.S. property marking over the "I" prefixed serial number, and model/U.S. Army marking. There is a "1" on the right front of the triggerguard bow. The full blue barrel is marked "P" on the left of the lug and "HS" on the right. It is fitted with standard blade and notch sights, checkered slide stop, thumb safety, wide hammer, short trigger, and arched mainspring housing, long grip safety, a pair of reinforced Keyes Fibre grips (without the screw reinforcement rings, like Singer or US&S), and a full blue "R" marked magazine.