Jon,
I’m afraid that the answer to your question is more complicated than a simple date.
There is no concrete date about when the XT4 (or any model) will come out, because it depends on so many factors, including:
– where you are in the country
– whether your dealer ordered the XT4
– what trim level the dealer ordered and whether there will be any manufacturing constraints associated with the particular configuration ordered
– the shipping/transport from the plant to the dealer (which sometimes gets held up by rail and trucks)
So because of all these factors, Cadillac gives us the (rather wide) availability window of “fall 2018″.
A few weeks ago, we were unofficially told that job one (series production of the first XT4) will take place at the end of September, around September 28.
That’s the best I can do at this point. Other that that, I would recommend reaching out to your local dealer to check on the order status of the XT4 unit(s) they have incoming.