It sounds like you are saying they are GM official publications. So their own publications conflict or are wrong?
Yes, but why are they wrong?
The first one "subtracts" the 1000 and says it's the 83rd truck built at the plant.
Why are you subtracting 1000? 1966 model year started at 100001...
The second one does not "subtract" the 1000 and says it's the 19,943rd 4400 series built at the plant, not total trucks built at the plant.
I believe you have found a typo that should have said it was the 18,943rd truck as we know from other GM sources that they started with 1001 in 1952.
Mike B
