I have seen a few, literally, so I suppose it is scarce. Just never really put too much weight into it. Have the back photo, and was waiting for some comments but all I hear is crickets.

You will notice on the probable Johnson BB sheaths with center keeper, it seems on most of them the keeper strap is often too long and is interfered with by the stone pouch (except for the third from the left), maybe another reason he moved it over. (Notice the BD sheath pouch runs the same interference.) Check out Ron's 5 sheaths and you will see what I mean. The third from left though does not have that issue and it also has a wide belt loop. Does that mean anything? I dunno.