I did the test drive thing at the Plano showroom (just opened). I'll go ahead and get the DDP upgrade as it's a hardware as well as software difference. DDP just has a lot more features and you can't just get an OTA and upgrade if you don't order it. It is interesting how Lucid pulled out a lot of features without DDP. To a certain extent - I appreciate what they did. I'm super hesitant to believe the cameras will solve all FSD problems. Personally, I think it's vaporware.
And, yes, if you take delivery this year - you get the $7500 - if not you're SOL.
The technical differences between the AGT and the AT are minimal once you add in DDP. The only 3 differences are slight trim materials, massage seats and battery - and small charging differences. Aside from those - they're the same car. However, with the smaller battery you get better rear seat comfort due to the 3.5" lower floorboard. The AT also weighs in about 500lbs less. I'm not sure what that does overall but I could see minimal improvement in tire wear.