N-frame hand question

[OldLawman]

In looking to stock up on a few parts as a precaution, I see that there seems to be two different over-sized hands - one with 2 pins, one with a third pin higher up the hand.

Can they be interchanged ? Does it matter?

Thanks for anyone with some knowledge.

 

[KAC]

As I recall the third pin in the hand is there to prevent the hand from bouncing back under recoil. The pin slides between the bolt and the frame. Of course I am ready to be told otherwise. Yes, they are interchangeable.
KAC