Some dealers do a good job of washing. Personally I researched and saw a member had posted to go and look at several of the black cars on the lot and see if there are swirl marks. I tried to make sure to also look at cars the same color as mine to see if there were any swirl marks on them. You might not be able to work your way around getting it washed. If your dealer does the perma plate on the interior then they'll probably wash it.
2013 E92 M3
Space Grey/Fox Red Novillo