Dear W, I am earning my coffee and cake now. The rear lug in the old posting will have a hook like in a claw mount. You push the rear mount with the hook into the recess and swing the scope down to the front mount.

When you tighten the front lever it should fully seat the rear hook into it's recess. I suppose it is like a claw mount in reverse or another version of the H&H system.You cant see inside the rear lug recess but the rear inside wall of the recess should be angled to engage a matching angle in the ring lug.

Regards,
GABE93