accepted for production, as I understand it. Which means the dealer has to have allocation for the truck, allocation for the trim level, and allocation for the options picked that may be on constraint.
Example, I placed my order for a Denali with LM2, Pano, Steps, Max Tow. The dealer didn't have allocation for the constrained LM2. A few weeks later they called and said they have allocation for my truck with the LM2, but max tow was constrained, and if I removed it, I would get picked up with a TPW of 4/11. So I removed max tow, put my deposit down and the next day had an order number with a TPW of 4/11.
So I believe the pricing is locked when it is accepted by GM, not by the dealer.
Some other dealers aren't as forthcoming with explaining constraints, ordering process, etc. etc.