RARE Colt 1878 Frontier Double Action Sheriff's Model Cutaway "M" Marked

Up for sale is this Ultra Rare Antique Colt 1878 Frontier Double Action Sheriff's Model Cutaway "M" Marked Revolver! The frame is marked .44-40. 3.5" barrel. SN: M. Metal left in the white and unfinished, small parts fire blued, checkered two-piece ivory grips. Short-barreled double action metallic cartridge revolver without ejector mechanism with six-chambered fluted cylinder. Sights consist of the standard blade front located nominally .35" from the slightly crowned muzzle and a groove in the top strap. The revolver is a cut away or "skeleton" model intended to illustrate the mechanism of the revolver. Barrel marked with the correct two-line style address for short barrels and reads: COLT'S PT. F.A. MFG. Co/HARTFORD, CT. U.S.A. with a single dash after the address. Left front triggerguard web is marked 44CF and the bottom of the barrel, concealed by the cylinder arbor pin is marked 44. The only external serial number is the letter M on the butt, indicative of a Colt factory "model" or sample gun. The left side of the grip frame is numbered 391, which is concealed by the grips.
The right grip panel is numbered 3 in pencil on its interior. The revolver is a full cutaway demonstrator with cuts on the left side of the frame to reveal the way in which the action functions, left side of the barrel to show the rifling, and in the center of one cylinder chamber.