After blowing the mystery car image up 5x and increasing brightness/contrast, it seems pretty clear that there's no tailpipe:
What appears to be a complete lack of a vehicle manufacturer logo stands out pretty markedly, I think.
Lots of similarities between the prototype and this car, namely:
-Lip at the top center of the trunk
-Horizontal ledge above the license plate
-General tail light shape
-Tail light straddling trunk joint
-Curve at base of trunk
-Body panel seams on corner of cars
-Curved shape of the rear window
-wider sides at rear wheels
If this is the alpha build, I think I might like the alpha backside better than the prototype...but I do like them both...