Tarawa,
You should not have to mess with the front sight or the bracket to set your upper and lower barrels for right and left convergence so they come together. The bracket can be simply budged over by using a flat pry bar to rotate the lower barrel around the top barrel.
The front sight /holding bracket will simply rotate around the top barrel because they put a groove partway around it for the crosspin. The mid bracket and the barrel inside it will be another deal altogether.
Good Luck Bob H.