I had the same issue as OP. At delivery this past weekend the software under Tesla T logo showed LongRange Dual Motor. Not underlined red as expected for performance. The delivery specialist took the car back and spoke with service manager at my request. According to him the car had the performance hardware but it just didn't have the proper software. They took it back to the shop and within 30 minutes it was back with the red underline in the software.
The window sticker i got says LongRange AWD as the title right up top. But in the delivery configuration section (right side) where the options are listed, it has Performance All Wheel Drive (and a $29K price tag). I checked the sticker for a P3D+ that's on the Internet and it shows Performance as the title instead.
I guess I am not sure if I believe my hardware being performance. Is there a way to check to be sure? Part numbers, etc. ? The car is fast alright although I have no way to test the 3.5s claim.