Might be a dumb question but if I were to bob my bed, (not sure how many inches) all that would be different is the mounting holes would sit farther forward (towards the engine) to mount up? Or are the pre-drilled holes on the marlin rear bumper matched up with holes already on the frame? Or do the frame holes get drilled by yourself when installing the bumper? Basically I don't know if the frame already has existing holes for the bumper to go into place.