I reserved online pre-reveal, got the invite on 4/15, and configured on 4/16. I don't have a VIN yet. I called Tesla on Friday and asked the same questions. At first I was told that I could not switch to AWD. When I pressed (nicely) and asked if anyone there could help me since my "3-6 week" delivery "estimate" is not going to be met, I was put on hold. After a couple of minutes, the sales agent came back, apologized for the hold, and told me that my reservation could be deferred for AWD, that Tesla would keep my current deposit, and that I would be looking at about "9 months" until I receive the AWD version, but it could be sooner.
The problem for me is that seeing how delivery estimates have gone so far, "9 months" frightens me. Even if they were on time with that date, I wouldn't receive the full federal tax incentive. I'm already going to miss the WA state sales tax incentive because they couldn't complete my "3-6 week" delivery. As much as I want AWD, I just don't think it's worth the risk of missing out on $3,750 of the federal tax incentive.