found this dealer information link showing weekly updates from GM to Dealers (information relates to what is available to order/or/what has been deleted/added, etc..
https://www.gmfleetorderguide.com/?year=2017®ionID=1&lang=1&divisionID=1&vehicleID=19913
https://www.gmfleetorderguide.com/?year=2017®ionID=1&lang=1&divisionID=1&vehicleID=19913
