As @
Desertnate says, it depends on how the car was sold. If the car was never previously registered, the mileage doesn't matter. The warranty begins at the date and mileage of sale. My FRS had 7 miles on it. My drive train warranty was 60,000 miles beyond that point (60,007 miles).
If the dealer registered the car, then it is a used car and the warranty would revert from zero miles for the purposes of symplicity.
None of this would impact what the warranty covers. I've personally had a car repainted by the dealer that I bought used with 10,000 miles on it but before the bumper to bumper ran out (the clearcoat spiderwebbed on it at about 25K miles).