floor plugs for bench seat racks in bucket seat car

These are rubber floor plugs like others in the floor pan, but a bit smaller than the rest. They are much larger than the fly window adjustment screw covers in the door. Still looking for a source...

All the cars got "drilled " for bench seats (actually these were probably in the floor pan before it was installed on the assembly line). Bucket seat cars were drilled through dimples pre-made in the floor pan, had the reinforcements welded in place over the inside holes and got plugs in the bench seat holes. (thank you, burdar for the pics!).