Except for the addition of the top switch and plate, they are all the same. The bumpers are the same. Ask Todd on this Board about the PP’s reproduction. It is close to the original.
70s are complicated by the midyear change of the instrument lens from pointed to flat. There was a used 70 cluster under the parts wanted section.
I have used cluster housings and used bumpers. Location would help as shipping bumpers is expensive. PM me if interested. Fred
The bumper from a base model Skylark will not have the holes drilled for the Buick nameplate across the back. Yes, I know, easy to add. And yes, a Skylark convertible implies Custom(350)/GS(455) only.