The Z-frame Governor will mount the X-frame S&W/Hogue .500 Magnum monogrip perfectly - as will the K, L, & N frames, too.
Try any .460 or .500 Magnum S&W for your handfit to the replacement grips before you order them. In padding that backstrap, they do add a bit to the trigger reach, but fit my medium+ sized hands fine. Certainly, the recoil help with the likes of the Win PDX1 .410 rounds is welcomed. The grips are avialanle on S&W's 'accessories' site or from S&W (1-800-331-0852) ~$36 + s/h + s/t.
Stainz