That's the opposite of what my dealer told me when I placed my order at the end of November. They told me sold orders are getting prioritized over stock orders. I placed my order with them and was told the next week that it was accepted and in queue. Thankfully, with the GM employee pricing sale going on last month, they were nice and let me get a truck they already had on the way to the lot instead of waiting for the one I ordered - which I'm sure would have been at least another month or two, given the 2 week Christmas break at the factories.
I did the same thing. Took a truck that showed in transit on the 28th and bought it with the sale and the Costco $1k. Hard to beat an $8k+ savings, although it does feel a little weird knowing I bought a truck I still haven't seen. When I was doing the paperwork, the finance guy told me that almost 75% of their sales in December were on vehicles that still hadn't arrived at the lot at the time of purchase. What a crazy market right now.