I don't wish to Contraindicate anyone, but I have a bumper hitch off a 49 3/4 ton pickup. Yes they were made. It is a cast iron piece with jaws similar to a vise. It is made to grip onto a spring steel bumper of that era. The one I have is a single bolt setup. I know of two bolt setups using the clamp mode. I also know that there are variants that use U bolt designs. While mine has a modern threaded one piece ball the correct part is a ball that has a bolt that passes through the ball and is threaded at the bottom. There may be some even different setups from a earlier era that were used.