Yeah that #2 with the brackets is funky. The rear cross-sill has to be longer than the rest to fit into the stake pockets at the rear. It also gets a vertical weld bead to the stake pocket. Here's another pic of my bed assembly (zoom in on the lower right corner where the line-up punch is sticking thru holes in the stake pocket and cross-sill.) I think you're going to have to get another rear cross-sill. Contact
Mack Products They have absorbed Mar-K's products, and should be able to supply with the rear cross-sill that you need.
I'm not seeing the holes for the front panel, but maybe you have that cross-sill turned around in the pictures. The sill goes behind the front panel.
