I haven't looked into them except to look in a few old parts books. In those it looks as though the pitman shaft is supported on either end with a bushing, and the steering wheel shaft in ball bearings. Unfortunately the pitman bushings are not listed separately. The listing is for the steering box body or cover with a bush in it.
Maybe someone who kinows this job from having done it will jump in here with the answers. ll
Still, the worst case would be that a simple brass bushing would have to be made to size. It isn't a critical job, so should be a simple task at the local machine shop.