Drill/Tapping for Jframe adjustable rear site?

[arizonaguide]

I guess it's a pinned arrangement.
Here's a pretty good writup on the details:
SMITH & WESSON J-FRAME High-visi

Headknocker is right though, before I DO anything I've got to see EXACTLY what there is as far as material in that area.
I would LOVE to be able to put an (easy to change sites) single screw mount there...but it all depends on how much material is there to work with. Once you get back away from the actual cylinder frame area, far to the rear, it would seem to be okay (as the factory did on the M63).

There must be enough (at least on the steel frames), if you look at the pictures in the Original Post.
But Bowen looks like they're just enlarging the existing gutter (into a small t-slot) so not REALLY removing much material from the area.

And I SURE can't make a decision on my "I think" and a "must be enough"...

I need to go take a look at the M63 and the 640P in person, and see EXACTLY what they did at the factory. Did they drill/tap?
And I need to pop the cover and take a better look "under the hood" in that area.

 

[arizonaguide]

For future referance.
B... : S&W REVOLVER ROUGH COUNTRY HEAVY-DUTY ADJUSTABLE REAR SIGHT - World's Largest Supplier of Firearm Accessories, Gun Parts and Gunsmithing Tools