Nope no secret should just come off. The hand guard may have a piece of veneer like material around the inside of forearm which might hang up on the barrel take care of removing. Usually there is instructions pasted to the inside of the hand guard on how to reduce recoil. Not sure how you could tell if barrel is matching serial number if my memory serves me correct the serial number is stamped on the ring that goes over the mag tub only visible with hand guard off. Good luck put some elbow grease into it. Jeff B