@chaotic_dragon:
I also downloaded the weapons.rar file which aztec posted and it includes one M16 with 30 rounds mag and a M16 with a 20 rounds mag plus a colt version of it with a second grip.

By the way: the image you linked too (http://www.investmentgradefirearms.com/images/M16.jpg) is not an M16 afaik but the colt version (CAR15) of the M16.
The colt version is shorter, uses a different (how do say?) "back-part" (I think its called "butt", not sure though) and is thus somewhat lighter.