I need help to settle a friendly debate with a buddy. He just picked up a beautiful first generation Standard in 4" barrel. He called it a Mark I. I corrected him and said in all generations--I, II, and III, the Mark is the bull barrell target version with adjustable target sights, and that Standard is like his. Was there a different nomenclature during the first generation years ?? Please tell me I'm correct; I can't bear losing an argument to my friend!!