I've got a like new, old, Model 18-2 with a serial number of K6393xx, and equipped with a target trigger/hammer, and grip. I have searched here and from I can determine mine doesn't have trigger guard screw and has a 4-inch barrel. Would this one be classified as a Combat Masterpiece? If so it would go great with my 1955 pre-model 14 .38 special which also has a 4-inch barrel. Any help as to date and any other info would be greatly appreciated.