If I had a better cell phone camera you could better see the Maryland “Historic” license plate (25 years old; limited highway usage).
Do you think he’s prepping for Pebble Beach?
(Best I ever saw was about 40 years ago, driving back from Lime Rock races. On the rear of the trunk of a clapped-out Toyota was painted “Rust Never Sleeps”. No cell phone cameras back then.)
I think he’s prepping to do something illegal.
If I were a cop and saw this I’d write him up for everything I could think of and not let him drive the truck unless the license plate were properly displayed. And I’d be sure to “run” his record and the truck’s.
Is there something improper about the license plate? I can almost read it in the reflection on the cars hood.
I think the plate is properly displayed. I put in the blue rectangle to protect his privacy.
I have, though, seen some cars around here with “anti-photography” plastic over the license plate to defeat the red-light and speed- cameras.
I was amused by the “historic” tags on a beat-up truck, and by the pimped-out static chains and (maybe) tail lights.
As long as he follows the rules of historic plates, there are no requirements that historic-plated vehicles be in showroom condition, or be show cars. What you call “beat-up” others call “patina.” 
In that case, the gentleman has my apology.
And you did the right thing. Kudos.
