The current Weapon Platforms with multiple receivers in Modern Warfare II are the following:
Bruen Bullpup Platform (Steyr AUG-based weapons)
Bruen Ops Platform (MCX-based weapons, as well the Honey Badger)
Bryson 800 Series (Mossberg-based shotguns)
Bryson Long Range Platform (Remington 700-based weapons)
For what are apparently legal reasons, many weapons and equipment featured in Modern Warfare and later games have minor cosmetic differences compared to their real life counterparts, while still sharing the general shape and appearance to the real life weapons and equipment.
