Nerf steps mounted to body??

[VortecJeep]

I recently ordered some steps for my 2005 Ram 2500. I haven't installed them yet. I didn't know it until they got here, but these mount to the body. Do most nerf steps for trucks mount to the body??? It mounts in 3 locations with 6 bolts. The only other ones I've ever done were on a jeep and it mounted to the frame.
This is a pic from the manufacturers website:
http://www.n-fab.com/view.just.image/src=/ecom/images/product/58.326.800x600.4-26-03_pics_011.jpg

 

[BigFish]

I helped a buddy put a set on his f-350 last week and they bolted to the body as well. I thought it was a bad idea but they seem fairly sturdy...