Sometimes at the factory after the car is assembled, the tyres are over filled around 50% . This is a safety precaution to prevent the tyres from "flat spotting" in case the vehicle is having to be kept parked for long period (perhaps a month or two) at one place. This is also done for vehicle being shipped from one country to another.
However, the dealership is supposed to check and correct the pressure prior to delivery. This is a standard procedure in the PDI. I guess they slipped up.