What is the significance of the stamp "Professional Model" stamped on the right side of the slide just to the rear and below the ejection port? I have several of these CM's. Are they any different (fit and finish, etc)? All I have seen are stainless. Thanks for any help available! I've collected Colts for years and I just got into the Detonics about 5 yrs ago. Not many people in my area seem to know much about them. I have really been impressed with what I have had the chance to aquire. Extremely nice! Seem to be a real workhorse and ahead of their time. Thanks again, Brad