Stop in for a cup of coffee
I wouldn't trust that one. AC Delco plays this game where they sell stuff as if its the OEM productions stuff when its not.
Bought one of their alternators last year. GM p/n and all that but it sure as hell never went through the GM supply chain, cause the components inside never would have been accepted. Junk. Production QC would have failed it in two places. The first before before they even assembled it - maybe even before the parts arrived in the plant. Every supplier down the chain needs to meet the same standards so they can be sure statistically that when assembled, they know it will work. Even 1 failure in a 100,000 is headache when it comes to a new car.
Sorry about the long paragraph. Hope it makes sense.
Bottom line is AC Delco may or may not still supply GM some parts, but if so, its not what they're retailing.