Carl, that has that threaded rod which was I believe a 48-50 set-up. You are right I missed the spring and nut you describe as shown here.
https://www.flickr.com/photos/advance-design_parts_co/8129470811/in/album-72157631868452754/
The twist version came later, this rod should have the previous bend as shown, it was actually straightened. There are many small running changes, knobs, hardware, length of and design of dash brackets. That spring and nut does control the rattle somewhat.