I have redone a few old piece of equipment including a few lathes. Most likely you only have scratches, you just need to remove the high spots, a 2MT reamer can cost between $10 and $30 plus shipping. All it will do by hand is remove the high spots to allow the arbor to seat properly. Just push it in, and turn using a wrench will clean any high spots, no need to clean and smooth out all of the deep gouges. Having a few scratches won't hurt it holding capability.
An the flea market on the Internet you can find both new and used. Or do as I would do and buy one from Victor Machine
https://www.victornet.com/detail/RMT-2.html