Actually, the can (3 oz. tube) he gave me was not GM. It's Wurth. So, I don't have a GM part number. That tube is laying on my work bench next to the car sixty miles away (which I will not get back to for a couple of weeks --darn it) or I'd give you the number off of it. BTW, nowadays it also comes as grease (or gel like Paul described it) in a tube.
Sorry to not be any more help... I suspect with this much info., you could find it at an electrical supply like hotroad says.