Sure, there's already a legit "Nerf" version that's a lookalike of the one used in the movie, but this Diatron sort of has that same over-under double-barrel look that the Quad Blaster has. Besides, reviews I've seen of the Quad Blaster toy have shown it to have pretty dismal ranges out-of-the-box. The Star-Lord Battle Gear set with a smaller single-shot version in blue probably performs better... but looks incredibly tiny to wield.
So... yeah. For all intents and purposes... Star-Lord uses a Diatron. At least, to me it was fun feeling like Peter Quill in the garage.
EDIT: In response to the debbie downers and pick-apart-all-the-fun-on-the-internet folks, yeah... I don't actually think the Diatron is an exact copy of the blaster. Just felt kinda fun shooting around in my garage after I found it. No need to get worked up a bit. "Calm down over there" ;)