short step cross sill question

[hobby67stepside]

Here is a pic (I hope) of the rotted floor carcass of my stepside. It is standing on the right side leaning against my shop propane barrel. It looks a little confusing. The 3rd from left is a 1" sill and the others are 2 1/2". The rear is different of course. My questions is: were there one or two more sills that totally rotted away or is this factory?

[kwmech]

My longhorn has the same type of set up--what I figured was the gap between was to allow for the rear axle to travel upwards without hitting the bottom of the bed, plus the frame in that area comes up- so the outer boards sit on the frame rail

[superchevy]

That is factory. The third from the left is a reinforcement strip, not a sill. Bolts to wood and strip only. Here is a link to Mar-K's site and a pic of the step bed:

http://www.mar-k.com/lateGMbed_kits.pdf

[hobby67stepside]

Thanks to both of you. I was pretty certain that there were no more cross sills or re-inforcement strips, but that is what this board is for. Thanks again.