Kevin!
I think you have a point there! They probably just changed the spring during production year without any notice. Sometimes if there wasn't such a big difference parts were changed without notice to assembly personell as well as dealers.
I checked the partsbook and the spring is not listed in section 13 - 72 Bumper jack. First Picture showing the 1964 partsbook. The bumper jack was one unit for Valiant and Dart. The bar was the same also. For 1965 there was the 1964 model for Valiant and the Dart had a separate one. They have also added the hook with a special partsnumber. Finally the base and the bumper jack was avaible as a set. I don't have a August or September or January parts book edition so I cannot tell when the change was made. Any one out there that has an early 1965 partsbook that can check this up?
I was going to install the spring that goes between each seat track so when you adjust your seat both tracks moves. However it seems that the springs might be different between the drivers seat and the passenger seat. It seems that the spring should be longer on the passenger seat!! My seats didn't have a spring on the passenger side and my convertible doesn't either!!:banghead:
The reason I'm wonder is that the spring should be routed through a adjustable hook so both sides operates at the same time.