The client brought up the concern. He has a number of trucks for his business. I checked with a couple of state inspection stations, got answers from Yes you do, I don't know have to call the RMV and "I've never seen a truck that old".
Since he was really wanting the trailer hitch I had to engineer something . Can't locate a hitch almost 3 feet under the bed unless you have some Very long trailer tongues.

My calculations say it will meet the 500 lb tongue/5000 tow weight.
Won't need the car trailer since you can just load it on the bed.

I was thinking of adding an X brace but suspected that I was going overboard on fully boxed 1/4" steel.