Ah, that Space Marine is created by DB is a parody on the Space Marine using some 'Super Deformed' style and other weird stuff.
The peace sigh is another anime referance, namely what all Japanese and anime characters do when facing a camera. (Also noted are the Vertical Hair Syndrome (VHS), disproportionately tiny head, and distinct series of muscles. Able to turn my head really quickly when I hear a strange noise, and hold up two fingers in the universal sign for "peace" after a particularly long battle (or photo op for magazine). - Exerpt from Something Awful's Guide to Anime.)
The smiley is just a chapter variant. The chapter is known as the Psycho Jester Clowns, their primogenitor chapter being the Ultra Marines, not Black Templars as their armour might suggest.
That, and the 'bolter' he is wielding is a heavy bolter. The ammo belt is just absent.
The head and shoulderpads are meant for the normal marine. Take a look at a picture of a Space Marine and you'll notice that his head is half over the shoulder pads, (A classic referance to the Roman gladiator armour who used their shoulderpads as a way of defence)
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Ah yes, 'tis almost the season to be jolly! Screw that! DB has side tracked again with my precious assignment and asked me to give him soemthing difirent to sprite. So I gave him pictures of the Vulture, an Imperial Navy Gunship, capable of wasting anything silly enough to cross it's path. So far he has completed the cockpit section. I'll post it when I can get my hands on it.