EZ Trak DRO

I finally got my EZ Trak (1993) running. The quill DRO scale is likely toast (more on that later), but I was surprised to see no DRO scales on the X and Y. Are the X and Y stepper motor encoders how the computer determines position? Is this reasonably accurate when used as a manual machine?

I have not yet gotten the computer running (not recognizing command.com currently) so I don't actually know what the interface looks like.