Depends on how you mount on the front. Both those rears will line up, as long as you match the front. High pic-rail gas blocks (very few) will take a same-plane front sight, as well as something mounted to the front of a rail/handguard setup. If you get a lower pic-rail gas block, then you'll need a front sight designed for that height. Several companies make them. Bottom line - depends on what you do at the front, not at the rear.