glock 23 i have has a lazerlite lazer rear sight on it, want to take it off and put night sights back on it, last time I took it to a gun shop and had them do the switch, is it to hard to do on your own? is the rear sight adjustable or one position only?? I just dont wanna take the other one off and risk losing my sight alignment incase something happens before getting it set, probably a newbie question but I've never taken sights off of a pistol before.