Aye, no other holes just round headed bungs. The bungs are obviously for rust proofing the inside of the sill during manufacture as it can't be painted inside then spot welded together. The rectangular hole must be a drain, maybe on the earlier cars there was a problem with moisture build up in the sills. So on the second generation cars they put the drain in. Nice of the 700cc cars to have been guinea pigs for ours.
