[unruhjonny]

thank you for the pictures.

This confirms my suspicions on two point regarding the seat tracks;

1. I had thought that the 1971-1974 seat tracks interchange for either side.
   
2. I had thought that the 1971-1974 seat track was the exact same setup used on the drivers side for 1975-1981.
   
3. I had thought that the 1975-1981 passenger seat tracks were unique.

If I can push my luck just a little bit, are you saying that my thinking that the 1974 & 1975 drivers side seat tracks are the same is wrong?

I do remember the cat hump affected the passenger floor, but don't recall any changes to the drivers floor.
I also know the seats all interchange (I had nice '79 black velour seats in my car for one summer).

I have two of the type in your first picture, and one of the type in your second picture.