Not sure on your model, but all the older ones with a front flex disc have a center sleeve on the input end of the driveshaft.
This keeps the trans output shaft and first section of the driveshaft in line when the flex disc is flexing under load. I usually
add a bit of grease here when apart. In the event that they are worn, [ usually out of round], they can be repaired without replacing the shaft altogether. It is a press fit and that may be the same as in your repair section that you mentioned.
There again , maybe the newer ones are different.