This Colt M1911 was shipped on April 10th, 1918 in a 4,400 gun shipment to the Commanding Officer at Springfield Armory. Little is known beyond that point about this pistol as the slide is the non-traditional Colt manufactured slide.
The A.J. Savage Munitions Company of San Diego, CA was awarded a contract on July 20th 1918 to manufacture 100,000 Model 1911 pistols. Authorization for this order was requested by the Procurement Division in an attempt to utilize manufacturing facilities on the west cost. Although no pistols were completed, they delivered some 68,000 springs of various types after the contract was suspended on December 4th, 1918. An unknown number of slides were also alleged to have been produced but there are no records to indicate that they were accepted by the Ordnance Department. These slides eventually made their way out onto the commercial market and some pistols have been assembled utilizing them.
While this particular pistol has no evidence of being assembled by the military utilizing the Savage slide, it's a very interesting and mystery to the M1911 collecting community.