I love my 6" model 19, I just got it, fabulous artillery piece! In my shaky hands it holds a nice 3" group at 20 meters offhand.
Once you shorten the barrel there are lots of front sight options. The gunsmith supply outfits can make you properly crazy with choices. Gunnar appears to mill a groove into the top rib and re-locate the old sights, which he must cut out somehow unless they're installed in a similar groove to start with? I can't see it, but Smith could hide almost anything with their Model 19 era finishing.
I always thought the sight base was integral, but after I saw the shortening job Gunnar had done on a stainless revolver (I think it was a model 66) where you could just make out some seams when you looked at the muzzle, I could imagine that they could be inserted before the barrel is finished.
Let us know what you learn, Mark!