What I have left of the belt line is the top 1/4" or so. I cut the entire straight portion across the back. The belt line viewed standing behind the cab is part of the stamping for the cab roof. The back side of the beltline viewed from inside the cab is lower part of the cab. These 2 pieces are spot welded together. The curves are stamped into the upper/lower cab pieces. No 3rd piece.
Dennis