Definitely bent, like Dan said. I see it has the cutout portion for the fuel tank to fit under the bed. Should be able to carefully straighten it. You may need to apply some heat to get it done properly. Heat will shrink the stretched bottom flanges.
Replacement cross sills aren't that expensive if you have trouble with it. Might be a little harder to find with Mar-K out of business now. Wow! I just checked and that particular cross sill with the tank cutout is almost $80 now. I'd be straightening it too.
