I put that same Choate flash supressor on my blued 582 RR. After much effort, I could't get the factory sight off -- it was hard-stuck. So, as the Choate instructions suggest, I cut off the factory sight just at the back side, which provided a guide to keep the cut straight. Took me about 10 minutes with a new hacksaw blade and cutting oil.
I used various grits of sanpaper to re-crown the OD of the cut barrel, and and a brass screw in a drill & polishing compound to lightly flare the ID (several YouTube videos show how to do all of this in detail).
Turned out far better than I expected. The new Choate FS was a tight fit, but a few taps with a hard rubber mallet did the trick. I used Red Loctite to secure the FS and the bottom set screw - I didn't drill/install roll pins; the FS is on tight and isn't going anywhere (I've shot ~100 rds since installation and it's rock solid). I was sure to align the sight before the Loctite set.
The whole operation took me about 1 1/2 hours, and the overall length of the barrel is only 1/4 inch longer than stock. Looks like it came from the factory that way.