The rail looks like a good idea. There is no reason it could not be installed on a S&W Governor. Looks like it would be a simple matter of drilling and tapping a couple of holes and screwing the rail into place. Given the Governor's typical use for HD, using a rail to mount a laser or light would be a help to getting rounds on target under difficult circumstances.
I almost ordered a Governor but waited, I bet next years version will have a rail of some sort. like the 325 TR
I think the other guy rail could be mounted on your Smith but it might not look like it was made for the gun, because it wasn't. Before you start drilling check the fit of 325 TR & the M&P 8 shot revolver that has a detachable rail.
Oh, this ain't something I'm going to try to do myself. I'd mess it up for sure.
No, I'll find a gunsmith for this. Wonder what a job like this would run. I was thinking somewhere around 100 bucks but have never even talked to a gunsmith. For all I know, he might be like my dentist.