accurate as possible leads you to pinned rear sights and trued front blades. But I'm not sure how reliable they are when taken from service rifle matches to the field. I"ve never had a single issue with a Holliger pinned rear sight, but YMMV.
That said one could put a receiver sight on the rail, and a aperture on a front sight base on the gas block too.
For all of that, I've just thought that standard A2 upper with sights and normal front sight on a 20 inch gun never were bad at all.
