changing points in an original style 1931 distributor

[fordblue]

I'm trying to change points in the '31 for the first time. It has the original style points that come in two pieces. the moving side is on a post with a 5/16" nut on it but it looks like there is also a nut on the bottom side of the distributor plate that turns too if it is not held. Do you have to remove the entire top plate in order to change points? All of the videos and write ups online show the updated, one piece point sets like used in the 50s 60s and 70s that I'm all too familiar with. Any assistance would be appreciated.