Yesterday I removed the rest of the rust off of the parallel bars using a plastic abrasive disk, as recomended by paul sellers. It also did a nice job on the faces and integrated bench dog.
I decided the pair was in good enough shape to leave alone. After a heavy coat of 3-in-1 oil on the threads and bars I ran through the operation a few times and was happy with how smooth it worked. Hopefully on Sunday I was start the mounting process on the end of the bench, one I lay out the leg mortices.