1965 Dodge Dart Charger
To continue this case and get to the bottom of it there might be a Product change that made this difference;
In 1964 Chrysler used a bumper jack with a built in hook. Using that in A-bodies was no issue. The only thing that needed to be stored with the spare Wheel was the bumper jack plate. Check out the picture.
When they changed the bumper jack to a new model with an external hook there was a need for more space in the recessed area where the spare Wheel is stored. Putting the spare Wheel up-side down and adding the plate in the bottom and then adding the hook meant that the large wing-nut could not be used. The rod is simply too short. Using a longer rod might have been the solution for this. But it cannot be too lolng cause otherwise it might come throug the trunk mat.
I will check into this and get back.
As always any one with info out there is very welcome with comments.