If the goal was to make people ask questions they succeeded!

Thanks for the confirmation that there is no functional impact for those slots. I did wonder if they were related to tooling or some other step in the manufacturing process.

I tried to look at backwards compatibility but hit a road block Both copies of the 29 - 54 Master Parts list that I can access do not have page 779. The online manual has a blank image for that page. The CD copy I have has 2 pages 780 but no 779!

The problem we have is that the outer portion of the slot on the right side somehow got broken away over the year. So we either need to repair that or decide to fill the slots on both sides.

I also agree with "why the center hole in the bumper". Lots of years and models (cars & trucks) have that

Rusty