Lot of stories of 250 distributors with sloppy shafts due to to wear on the top bushing...I pulled the shaft and the bore is worn egg shaped but there's no bushing that I can see.No bushing is shown or listed in a 1971 GM truck master part manual...
So I suspect the shaft rides on the bore in the aluminum housing?

Quick answer: I don't know.

Mine wobbles a bit too, and ignition when checked with a strobe light was a little jittery. Install a Pertronix magnetic pickup and it settles to a rock steady, even pulse, shaft wear no longer affects timing. So a worn distributor "becomes like new" again. Still need to make sure the advance parts work ok.

Send them to Jim Linder at Bubba's Hot Rod Shop. He rebuilds distributors, even has a two day class on rebuilding distributors. He just did one of mine, it was perfect. Motor runs perfect. Fair prices, excellent work.

I bought a Cardone rebuilt distributor for 30 bucks.The shaft and advance unit are a foreign made joke. But the housing has a bushing top and bottom unlike any stock distributor. I put a decent GM made shaft and advance unit in the housing...Better than new.
I believe "Bubba" has cut back on his work load and may not do certain types of work any longer.

Every 250 point distributor I ever checked came from the factory with a bushing that was replaceable. GM used to sell them for a dollar or so I doubt that they are still available from them but the trick was install two of them instead of one and you never had another problem. In today's world I just but an after market Hei unit on and have a much better system for around fifty dollars including the coil. I used MSD units in the early 2000s but the parts (cap& rotor) became a pain to locate so switched to using new alum hei units.