Typical pre-pandemic timeframes were usually 8-12 weeks. Decreased production due to pandemic and also slower shipping also due to the pandemic has ballooned the wait times. It might be less than 16, but I wouldn't guarantee it. Also, did your dealer say they had an open allocation? If they had one, they should have had a suspected TPW (Target Production Week), though not guaranteed until GM actually accepts the order into production. (your status of 1100 does not indicate that the order is accepted by GM, only that the dealer created the order successfully)