Depending on where you are located, four weeks sounds a little quick. It took about six weeks for my Acadia to arrive, and I believe that this is a more typical timeframe. After ordering, you should call your dealer at least weekly to get an updated Order Status code. This will give you a better idea of when your Acadia will be delivered.
Actually, I was surprised to find that my turn-around time was just about four (4) weeks. I was pleasantly surprised, as you might imagine, especially since the dealership kept telling me it would be anywhere between 6 and 8 weeks. I guess they've been turning them out pretty quick. The only problem, depending upon where you live, by what means of transport, and how far you are from the drop-off point will ultimately effect your actual delivery date at the dealership.
Note: If it's on a train and possibly sitting in a trainyard, insist that the salesperson/dealership "Red Tag" your vehicle for priority delivery.
Oh . . . and :ditto: what Twindad posted. Remember . . . weekly and be insistent.
Welcome to the forum. As noted by detnick, if you will post your location in your profile & also the model you are buying in your signature (click on the Blues Clues link in my signature to see how to do so) this will help members answer questions such as these.
I'm in FL, we were among the last to be able to order the 2009 models. My order went in on 8-7 (code 1100) and it was built 8-25, shipped 8-26, at the rail yard here in FL 9-9 and it would have sat there if not marked "hot" or "red" (whatever your dealer calls it) for who knows how long- we stopped in on 9-15 and our salesman had to be prompted by another one to do this for us.