Detonics .45 on the frame is normal. The same frame was used for all caliber Combat Masters. The Detonics armorers fit the .38 or 9mm slides and barrels to the same frame, and used a different ejector and magazine. Typically the Detonics craftsman etched the frame's serial number on the matched slide and the barrel. If your slide and barrel have a serial number engraved (with a hand scrolling tool) with the numbers corresponding to your frame, it probably was built by the Detonics factory.