Kinda hard to tell from the pics but it does look slightly crooked in one of the pictures. It may not be anything to worry about but I could never live with that, at least without having it inspected. The mounting holes are definitely not slotted but there may be enough jiggle room in the mounting bolts to loosen then re-toque. On the other hand, the mounting bracket for the pinbox may be tweaked, bent or mis-drilled? I guess there is also the remote possibility that the trailer frame is tweaked. I notice it's a new pinbox, I'd measure it up to make sure it's squared up. Whatever it is, I'd want to know what's going on....especially with a new rig.