Could be. Could also be something they never considered for the actual car, but needed for testing.
I think if they were an option it wouldnt be "prototype" brakes, but "optional."
As I said, I think they knew the brakes werent serious enough, so while they were turning something else (aero, suspension settings, etc...) they had those on there so they could keep going. Same thing with the radiator, or oilpan. Something that takes away that particular restriction, so you can test others. Or do tests more quickly.
IIRC those look very much like brembo 6-pots