Great post my friend! Sounds like the Vendor did not know of the issue until you brought it up. We'll have to take his word at this for now.
Now keep us ALL informed on how the replacement part shipment goes, and more importantly how that Vendor has fixed his system to ensure other Pontiac folks don't go through this.
We must keep the Vendors and Sellers on their toes, folks! We've ALL been through the "wrong part" fiasco on Ebay and other sites. If you don't [censored] enough they won't fix the system.
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?