So, with the engine year confirmation from Dad's and the door post plate number info, the only question remaining for me is
why the vehicle ID number on the California title is different than the door post serial number.
I'm in no doubt that the truck is legitimately the same truck as I know all the owners except the original farmer purchaser.
It has 52,000 miles on it, by the way.
Again, thanks to all of you for the help on this. I was out in the snowstorm last night getting that last engine block photo!