Some haulers were used by multiple teams and basically "handed down" as the trucks aged.
There's a lot of that van body that reminds me of an Oleynik body; a lot of the contract racers had Oleyniks.
Looks pretty basic, like hauling tasks only, not a support rig at the track, but of course things could have been changed over decades.
The old trucks ride & drive, when compared to the newer stuff, a lot like a '60s car vs '00...but are so much cooler.