Yep, it has an upper receiver assembly that is serialized pinned to a lower assembly that houses the trigger. Obviously they are targeting the AR platform, but a lot of firearms use two piece receivers.
(A) A FIREARM DESIGNED TO ACCEPT , AND CAPABLE OF1
OPERATING ONLY WITH, .22 OR LOWER CALIBER RIMFIRE AMMUNITION,2
UNLESS THE FIREARM HAS A SEPARATE UPPER AND LOWER RECEIVER