The original owner was probably a big guy. That caused them to lean to the left. The springs on the drivers side probably need re arching.
You think he is joking but there is more truth to that than anything else.
Look at any older truck or car for that matter that is normally driven by one big guy with no passengers riding with him and it will lean a bit to the drivers side.
Having or rearching the springs so that all of the springs matched in arch would fix the problem.
When I was doing front end work in the 70's I would have to put AC spacers on the springs on the left springs of some Pontiacs that had heavy drivers and sagged on that side.