Ford did some weird things though.
My opinion is they changed certain things to appeal people more to the new year model.
I can imagine salesmen stating, "Don't buy that one! It's a year old, see the differences!"
Only thing I can think of.
Truck: 1981 F-150 Explorer / Engine: 300-6 California MCU Feedback System / Trans: T-18 - 4 speed / 2.75 Ford Rear Axle Open Diff.