No - that screw holds the sight to the slide. The two screws on the right side of the sight are for adjustment. The rear one is for elevation and the front one is for windage.
Thanks for the tip, don't know why I didn't think of that..... must be my advanced age!You can loosen the retainer screw and move slightly the entire sight to right or left - you have to do this with windage in center position - and there is a limit to it's movement and still screw down properly. Mine is all the way right. Then use windage to center from left or right - worked for me.