The Swiss were certainly not fools!!....

Luke, The main thing was to add the "bump" at the bottom of the front grip strap, so that the pistol felt like a PO8 in the hand. They also cut back the external raised portion of the side plate, increased the diameter of the round checked portion of the take down lever and changed the shape of the safey lever and the trigger. At some point they also change the extractor marking from "loaded" to "Geladen" and the safely marking from "Safe" to Geschert". Of course the grips had to be changed to match the new frame design. All the above changes except frame & grips, will be also seen on the 06/71s made after 1973, after they used up the remaining old style part. I do have both styles of parts available new.