I have a 1950 GMC 1-Ton pikup and I have the shock absorber brackets on the rear drive shaft which are mounted within the frame, and dont line up with anything. I do not have the upper support, and cant figure out where the upper support was located for it seems that it could only mount to the bed box horizontal rails, for its the only object above the lower supports, which is perculiar. I looked at the manual and it said "if used" perhaps there wasnt any on this model, but why are the lower supports there, hmmm? I need to figure this out for inspection requirements.