In this case, the MCAS may or may not have been in operation, it’s not an anti stall device, it just adjusts the handling characteristics in pitch to match that of the earlier models by subtly repositioning the stab as needed during high AoA manoevres.
The accident aircraft were suffering from erroneous AoA input which moved the stab continuously Airplane Nose Down. It would be safe to assume that the demo aircraft was fully serviceable and the MCAS if in operation was operating correctly.