I have a set of lights and harness that I clamped on the back of the flat bed to be, mostly, legal. The sellers were trying to talk me into buying chains, but the temp was coming up and the roads were seeing some blacktop by the time I left, so I declined. Going back up Wolf Creek Pass, I was regretting that decision...
BUT, I made it. If I had it to do over, I'd put chains on.
Thought I had a pic from the back, but can't find any. You can see the lights on the end of the frame rails here. This was at a rest stop in IA.