That's cool Trent that does look a lot like the M4.Osama was supposedly killed with an H&K M416 which is actually a different type of proprietary system. It's based on the 5.56 cartridge but utilizes a short stroke piston system and a few other modifications. It shares almost no parts with an AR15, M4, or M16.
Here is the civilian legal version of the H&K 416 but it does actually share more parts with the M4/M16 platform than the real HK M416.
MR556A1 - Heckler & Koch