Im willing to bet it was in an accident and the auto body shop didnt replace it with the S badge just out of pure stupidity.
Even if it comes up clear from acciedents on carfax, autocheck, etc- it could have still been in one and just not reported to the police or insurance company.
Open the trunk lid, check the underside and see if it has the Porsche stickers from the factory in there and that they match the other numbers on the car.
