Trust me, it's the 991 cab according to my "source". The timing makes sense as the car is going to be in showrooms in early Spring. The coupe was shown at Frankfurt in September and will be in showrooms 4 months later in December. The cab will be shown at LA and in showrooms within the same sort of timescale

Don't forget the cab's have been spotted driving around California in the various convoys practically undisguised.