The do a run around the test track at the factory for all cars to check to make sure the thing works. (During the factory tour, they said that this is considered one of the best jobs... get to take out new cars and "test" them.)
My car had about 35 miles on delivery (at the factory). It was one of the first 85Ds so I imagine they ran it thoroughly.
They all show 50 miles on the paperwork.