I have 2 different top hold down brackets is it a year thing?

[cleszkie]

Originally Posted by hemi43

Mine is a 70 double wall, and no notches. Part # 3980064
If you notice on my part, there's a wear mark where the notch is supposed to be located. I'm thinking GM modified the part for later years because of interference issues with the latch. Probably caused an annoying squeak !

I completely agree with this. That wear mark can be seen on the set of brackets shown in this thread.