I have not seen replacements anywhere, though you might try Christian Ondrak, OK Parts and Engineering in Germany. He may know a source. Other than that, your best bet is to machine up your own. Mine in front of me at my shop both use the pins as well. These are available as hardened gauge pins from several machinist supply houses in any metric diameter you could wish. Hardened all the way through, they do not wear, but the brass bushings still will wear. A moly cam lube helps somewhat here, and should last the service life of the T.O. by which time the bushings will need replacement again.
I annealed my brass sheet soft, not dead soft cheery red, but just turning blue, as brass hardens with working. By the time it was rolled to shape, and pressed in place and finish reamed, it was hardening up enough to provide a good service life.