so on my '74 project when i was striping the interior i found a curved metal piece with a plastic end on one end. it looks like it could be a track? this is for the side rear windows by the way. anyway this part was in the bottom of the quarter panel where the quarter and the rocker meet. its not rusted and it doesn't look like its broken. the other side has the same problem. when rolling up the window the window also seems to go forward and get stuck. so anybody know what I'm talking about?