That will be 1 short drive shaft with a 6 speed.
LOVE IT!
But you gotta keep it that nice clean unassuming look on the outside.

There is too many nice clean first gen cummins out there for sale with 100,000 +/- miles to bother with a 450k mile truck. The motor may be fine for another 400k, but that truck has got to be beyond worn out.

Not necessarily, depends on how well it was taken care of and not abused. My 91 was just about to roll over 300K and was in perfect mechanical condition until it was wrecked. I worked it hard towing and hauling. But me and the previous owner took good care of it. I've had several vehicle go 300-500K. "worn out" is a rather subjective term with me. If it can be repaired, it is not worn out. Just boils down to how you define maintenance, which to me includes replacing any part that needs it. My transmission was overhauled a month before the wreck. The transmission shop said all it needed was new syncros. It got new bearings and shift forks anyway.
Bottom line is INSPECT THE VEHICLE BEFORE YOU BUY IT. I've bought low mileage vehicles that were a POS due to non use and neglect. And I've bought high mileage vehicles that were in perfect mechanical condition because they were taken care of.