It's called the "floating" hand. Introduced around 1986, and discontinued not long after. Many are indifferent, or even like this system better. To me, it's one of the worst modifications in terms of fitting and function that they've ever tried in the action. Personally, I'm glad it "went away".
The pin you are seeing is the top of the pivot pin for the hand body. If desired, the floating hand assembly can be replaced by simply driving out the hand pivot stud from the trigger, and replacing with a regular hand with the traditional stud (pin) fixed in the hand itself.
Some fitting of the new hand may be required.