Between 1960 and 1975, approximately 500 Sheriff's Models manufactured. First of these were marketed by Centennial Arms. They have 3" barrels and no ejector rod assemblies. Frames were made without the hole for ejector rod to pass through. Blued, with case colored frames; 25 revolvers were nickel-plated and would bring a sizable premium if authenticated. Barrels marked "Colt Sheriff's Model". Serial number has an "SM" suffix. Chambered for .45 Colt cartridge. NOTE: Add 100 percent for nickel finish.