The latch and striker for the 72 is 200% different than that '88

There is no bushing on it either, which is a great fix for the square bodies.
Sounds like the weather stripping is new or at least is great shape. If the latch operates smoothly and doesn't BANG into itself (check the top of the latch for grooved wear mark) than I say you need to adjust the door or the pinch weld that the weather stripping holds to.
If the door gaps are good and it is flush with the outside of the cab (meaning, not pushed in farther than it should be) than I suspect the pinch weld. Watch the door close from inside the cab and see where the weather stripping is compressed the most. That's where you'll need to push the pinch weld in more, away from the door. Most often it's the floor (from abuse) or near the dash that's the tightest.
PS> a door that is flush with the front fender isn't always correct as the fender can be changed. It's tough to line that up properly. I have no tips for that LOL