Tracking issues on '72 4x4

[joeydurango]

After looking for a long time, just found a '72 SWB 4x4. Drove seven hours to check it out, made the call, drove it back home. Drives good, needs some front end/steering work (play in the system), but it does drive straight. Frame looks good (considering it's 40 years old) to my eye, although I'm not a trained auto mechanic.

The one issue that stood out when deciding whether to purchase or not was tracking. Drove it through a bit of sand in a straight line, and checked out the tracks. Driver's side, front and rear tires are on the same track. Passenger side, the rear tire rides a few inches inboard of the front. The rear axles on the SWB 4x4 are shorter than the front, I believe, so it appears that the rear axle is shifted to the driver's side a bit. Tricky, though:

-The cab and bed are straight, aligned well, and other than the bed being *slightly* tilted to one side (something I've seen on several of these trucks), everything looks good. Cab and bed being mounted to the frame, it makes me think the frame is straight, and there's no frame damage I've seen.
-The wheels are all the same (although I'm not sure whether the rally wheels were made in a bunch of different offsets - they look the same).
-The tires are all the same.
-The rear tires have a good bit of wear and the wear is even.
-It drives nice and straight.
-Rear axle looks good.
-Rear axle halves measure out the same from leaf to drum.
-Suspension looks good to my eye - but since it's the only thing between the frame and the axle, I'm wondering if I'm missing something.

Sighting down either side, the front tires sit equally (lateral position) in the fender wells. The rear tires do not - the passenger side is inboard, confirming what I saw in the sand. Anyone have similar issues or have ideas on what might be going on? If it's something really odd, I'll have my shop diagnose, but just curious if it's a known issue on these.

Even if it is something odd, I'm not too worried - the previous, older fellow who had the truck had driven it since 1992-ish and never noticed a thing.