I can tell pretty easily, post pics of the top lens, bezels. They made two styles, 70 and SOME 71's had the slip in bayonet style, later 71's and all later ones were the 2 bolt style. All other details were the same between the two years. The reproduction handles are all 2 bolt style, the bare handle is pretty close but is not made of two parts like originals and so unlike originals, are the same thickness top to bottom, the grips, bezels, and top lenses have differences that a trained eye will notice.