The "Oversized Walnut Panels for Security Six" (as labeled on the Ruger Accessory Parts 6 pack box from Ruger) are a single screw thru the frame. Six series revolvers that came with them installed from the factory had a suffix of "T" in their model number, ie, RDA-34HT (Security Six, .357 Magnum, Blued, 4 inch Heavy barrel, with Target grip panels)