This one should keep you guys entertained.
i think its the first one from 
And i may have some of my answers wrong, these are the only photos they had.
Barrel Lug: Pinned
Battle Sight on RSL: Uncertain
Bayonet Type: Spike
Bayonet Lug: Late Non-Cut
Bolt Carrier: Late Non-Cut
Gas Tube: Late 2 Piece
Gas Block: Early Milled/Late Cast/Late Cast w/Round/Uncertain
Receiver Cover Takedown: Normal
Rear Sight Block: Early Late Cast
Serial Number Format: X Digits, 711507
S/N on Components:
S/N on Stock: Last X digits, leading zeros, Small/Medium/Large Font/Uncertain
Stock Swivel: Bottom
Trigger Group Type: Early Milled
(Whoops, i knew it was odd looking though) and either a flush magazine (5 rnds) or a strange angle photo?