Can the flue collar on the Hearthstone Mansfield be removed and then reinstalled, in position, in order to get it to sit back into an existing fireplace opening? My fireplace is 28.5" tall and the Mansfield is only 27" but the flue collar makes it 31" I have a 40" wide fireplace and plenty of room up top once the stove is back in there but getting it past the front edge is the problem.