I had looked into these a couple months ago also. I emailed Krebs and asked when they thought they would have some of theirs redy and they said they didn't know because all shop time was being used on the KTRs. And being basically a tightwad anyway, I decided to try and make one from AR sight parts.
I bought some smooth covers to experiment with. 3/4" square steel tubing works pretty good for a body and the AR aperture, A2 index screw, flat spring and either knob or the numbered indexing plate for parts. The hardest part is figuring a way to ratain the flat spring. I made a couple blocks and welded them in, but they could be screwed or soldered too. I made a couple, 1st with A2 and the other with A1 aperture and drum parts, The A1 is more streamlined, and I don't really screw with the windage once it was zeroed so the knob was just in the way.
They work great, covers are very tight, no wandering zero.
More than one way to skin a AK.