It's a Winchester 1300 clone, so any parts for the 1300 will fit.
fair enough. I can't vouch for barrels and stocks, but I do know that the B square receiver scope mount, part #16900, will fit the 320. I have heard reports of people putting the surefire forearm w/ built in light on the 320, but take that info for you paid for it.The action is "based on" the 1300, but I have yet to see where anyone has confirmed that Winchester barrels, stocks, forearms and such will interchange.