I have a 72 Cutlass Supreme with rear retractable seat belts. The retractable latch side is visible, but not the other side that the latch would attach to (the buckle side?). I have not removed the rear seat bottom yet to see if they are behind or under the rear seat. Can I correctly assume that if they are present behind or under the seat, they would be a short length - just long enough for the buckle to be visible to allow the latch to snap in? See photos below.