If it has a bolt inside the magazine well, then it may be double-lugged. Some lugs are welded on and some lugs are not welded. The non-welded ones requires the barrel shoulder to be turned farther back and a threaded recoil lug is sandwiched between the receiver and barrel shoulder, like a Savage or Remington recoil lug.
Ask him if you can take it apart and inspect it since he's your friend.
Tony.