'73 bumper brackets on a '76 ?

If it had all 3 mounting holes it probably came from the factory with a non-shock mount bumper. I kind of assumed that the factory had planned on returning to the shock mounted bumpers at some point, which is why the mid to late '74 cars got all 3 holes, so whenever the production on the shock mount bumpers picked back up they could just add them back in without a frame rail production line change.

Mine was a June build, and it had a non-shock front bumper but all 3 mounting locations as I showed above.

I converted the rear bumper over to standard bumper brackets too, first with some home made brackets and later by welding up the rear pan and using the earlier brackets.
I went back and looked at my own damn pictures and just confused myself more, LOL. What I do know for sure is that I didn't have to drill no damn holes in the frame. Which is right in line with what you're saying. But now I'm thinking maybe mine didn't come with the shocks in the front and I just dreamed that s***. Who knows, I got the CRS. I converted the back of mine also.01414_ioKTgtmKw6S_1200x900.jpg 00i0i_5IfVEhxX4i0_1200x900.jpg