Beltwheel lockring unscrewing itself

I don’t think I actually have a locating block - the only parts on attached to the KS-3 are the kickstand bracket, kickstand, and the bolt that holds them together! Looking at Bill’s handy pictorial guide, I just realized what that part looks like, and that since I can see the ridges where the locating block should be, it’s definitely not there.

Likely it got lost when I had a bike shop swap the KS-3 when when the original one locked up on me a couple years ago.

Any idea where a replacement can be had?