The front sight housing is heald on by a tapered roll pin...thorugh the center of this roll pin runs that screw and nut you see on the outside. Remove the screw and nut, and you'll see the roll pin...and that bad-boy is usually driven in real tight. Will need a good punch or just the right diameter...too large, and it peens the hole...too small and it expands the roll pin. The weight is as you guess, helod in place by a grub screw...there is a flat on the barrel for the grub screw, and if you remove the weight completely, will have that odd looking little flat spot.
Here is what I did. I took off the front sight housing, flipped it around, and rattached it. this leaves a "spigot" like hollow tube sticking out over the muzzle. Can then move the barrel weight up to contact the now-flipped sight assembly. Attach your muzzle device to the hollow spigot. At first, used o-rings to hold it in place...worked fine until I lubed the system, which sprayed some lube from the barrel....which got on the o-rings....which resulted in shooting the muzzle device off the gun. Is more firmly atttached now with a small detent and grub screw.
