GM has no ability to tell the dealerships how to sell cars. All they can do is set the MSRP(Manufacturer SUGGESTED Retail Price). The dealer your so "in" with is lying to you.
A dealer can sell a car for $1.00, they will just be taking a large loss. The dealer could also sell the same car for $1,000,000.00. AND GM could do absolutly ZERO about it.
GM sells the cars to a dealer. The dealer in turn sells them to us.