Found an example of the plastic bucket seat hinge covers without screw holes. Obviously there was and issue, so these were changed. This is my only example, had only heard about these from a 429CJ friend.
Am guessing that the mold was modified for a counter sunk screw hole for attachment. Notice the upside down "3" in the casting number? Looks like the original design was a friction fit. Not sure how long this style was used.
