That's what happened when I ordered one of the first ecodiesels in 2013. They all had to sit in a parking lot waiting for the DEF systems to arrive and then get installed. It was a big day when the status page finally showed it was loaded on a train for transport to the dealer.
It probably also heavily depends on supply chain issues WRT the specific model/options, and then it can get delayed after ‘basic production’ if it then has to be sidetracked for installation of certain things like running boards, mud flaps, PPF, etc which are often done at a secondary installation facility at the factory.
If your order is ‘simple’ it can be done right now in a day, but if it was placed behind a bunch of others who get the limited availability parts first, you could end up with supply chain deletes or stalled assembly due to secondary facility backlog for similar reasons.
it’s just a mess these days, on top of normal model year changeover.