B.A.R is correct in his comments. However.......If a things worth doing. It's worth doing CORRECTLY! VERY good to get into the habit of doing that!.......
The gas retaining ring/ clip for example. If not fitted 180 Degrees round from the position where it is shown in your picture. May WELL catch a finger/ clothing etc in handling. That is WHY it SHOULD be in the position just described! & as for the hinge pin screw. Yes technically it doesn't matter which side it is in. The Rifle WOULD function if it were a live example. But, esthetically. It would LOOK nicer in the correct plane. Yes?..........
The point of this forum is to HELP others with advice & assistance where possible I believe. We all have spheres of Knowledge that benefit each other. Otherwise, well. What is the point?............Just my Two Pennies worth.