Yeah, $till a my$tery...It's still a mystery
I'll give the dealer a call.My dealer in eastern PA had a shipment of replacement jacks last week. I stopped by and had a new steel jack in about 10 minutes.
Call the dealer parts department to see if they have them. You could be waiting a long time to get a invitation from GM to get the jack replaced.
The new metal jack was much better constructed than the mostly plastic jack.
The first time I paid any attention to the plastic jack was when I exchanged it at the dealer. I was shocked how flimsy and cheaply it was made.