What size of rotors are factory size on the front on a 2 door model Cutlass.

When two sizes were available, you're going to have to physically measure one or remove it and match it up at the parts store. Sometimes the dealer mechanics can tell by the options on the car. For example, I know my '88 Grand Caravan has heavy duty brakes with larger rotors and pads because it has 15" wheels instead of 14". Without knowing that, I would also have to remove a rotor to match it up.