First off, didnt most pilots have a line of sight OVER the guns sights rather than having to look through them to fly??? Planes like the Tempest and the later sights used by the USAF in WWII were not limited to a small 4in square piece of glass mounted on the instrument panel.
For me, the jury is out on this one because of all the other "realism" factors involved. Technically, HTC could give all pilot a locked default view of X height up from the seat and then require the pilot to dip/move his head to view the gun sight. Think about it. Did the fighter pilots fly around %100 of the time looking through the sights? I doubt it. Imagine the crying if HTC implemented that type of realism.