I wish I had more experience with older Campy stuff. I have found that on some frames the Campy RD will affix to the drop out solid & not movable. Other frames the Campy RD will hang loose or movable.
Am I assuming that a correctly mounted RD should hang free to move for & aft. The cage spring pulls the chain & RD to the correct position. This requires a pretty strong spring.
Someone correct me if that is incorrect.