Yes. The Bravo Company MFG Bcm gunfighter Stock Kit Mod 1 will fit to the AR15, DPMS, and Armalite platforms. This kit comes with a standard carbine buffer that may need to be replaced with a heavier buffer in order to ensure proper functionality of your LR308 rifle.
Yes. The Bravo Company MFG Bcmgunfighter Stock Kit Mod 1 includes a carbine buffer (3 oz), which will function fine with a 16" barrel and mid length gas system. This kit also includes a Mil-spec receiver extension, locking nut, Mil-Spec Carbine spring, and BCM QD swivel mount end plate.
Yes, this kit is made for the AR-15.
Yes, those are included.
Yes, it comes as pictured.