My bottom photo of the listing will show that notch being referenced in the base.The scope rings slide onto the dovetails of the double square bridge receiver. On the left side of the rear bridge there is a notch that will index the QD scope rings for perfect return to zero.
Thanks to @One Day... for this picture on a CZ550, but it's the same as a 602 setup...
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@Green Chile - Beautiful rifle. I can't even imagine what you are keeping to have this on the sale block.