Early Karsten I PING 1 Iron

In the very early 1970's as a young golf professional, I was awarded a set of PING clubs as a member of PING professional staff. Somehow, over the years I also acquired this early KarstenI PING 1 iron, which I once had the skill to use as a "driving iron" - especially during my rounds on the links in Scotland. Anyone who might give more info on this old club?
17-4 stanless, right-hand, original PING shaft, serial #61167.