HankC1 and StoneHorse are correct even if they are not experts. Experts can remove and install a rear sight with their eyes close.
but they are often misunderstood in there writings.
But a picture is worth a thousand words and I also agree about the drag marks especially if you see them on several new guns!.
I am not an expert gunsmith but I was a top notch Mechanical Engineer 25 years ago before I started designing computers. My freind trusted me in installing his rear sight on his SP-01 just about a week ago. I took them out looking from the rear of his gun just like if you where to shoot someone. I took them off right to left and installed it left to right just like in HankC1 link, and his newly installed sight exhibited a drag mark on the right side where there was not one before we installed it.
