Agreed. But with the way it is now, you wouldn't drill the whole recessed area out. If you drill a hole just large enough to run each side of the stems through to connect in the middle notch (see pic above), the remaining material should be enough to provide a base for the cups on each side, then the bolt in the middle notch anchors the RX Arms QD cups in.
Would love to see if @RxArms has / could try this with the 61171. If it worked it could solve several problems, providing QD cups on both left/right sides of the stock.