http://www.coldwarshooters.net/index.php?main_page=product_info&cPath=17&products_id=101 I am planning on getting that for my rifle. But I am pretty much a noob when it comes to ARs. When I get that upper, it doesnt look like it has a rear sight. Will I need to buy a rear sight for it? If so, is there an universal mount for the rear sight for that particular upper? Also, when I choose to get optics in the future, what mounts do I need to get? It looks like theres already a mounting system on the upper, but it doesnt look like Weaver mounts...which is what I am most familiar with. School me.