I bought the white trunk sliders to install on my (very early) 68 Charger but when I went to install them, I noticed that the trunk hinge cam where the FSM says that the slider should rest on looks very different from the "box" style in the manual (both left and right hinges have the same set up). Can anyone tell me if these hinges might be from another vehicle? They look and operate fine except for the lack of cam. The torsion bar rests on the hinge now because the cam is so small. Any help would be appreciated.