The numbers are printed on the same ring as the rubber grip and it spins freely on the silver barrel. There is a very small amount of play between the two pieces if you push them front or back.
Here's a picture of the back side. You can actually see the screw under the grip to the bottom right. The piece that threads onto the back of this has a lip that catches that screw and stops the gauge at the near/far markings.
Also, thanks for taking the time to reply, I appreciate it.