Would that every poster asking questions started with such a good array of photos.
One other might help. One of the rib. Is the rib just plain matted or does it have a Parker Bros. legend? Or, the very rare "PARKER, MERIDEN, CONN. U.S.A." legend?
Parker Pages lists 240466 as possibly the last VHE 20-Gauge made in Meriden, but I don't see anything definitive on the last Meriden 12-gauge.