Let's clear up some misconception:
1) Floor mats are not included with 3 series cars including the M3
2) Most dealers go ahead and purchase the floor mats when they purchase a car and will provide you with them, however, you are paying for them normally within a "dealer fee".
3) I have seen some dealers just provide the standard 3 series mats that say BMW instead of the correct M3 ones. Tell them you want the M3 ones.
4) If your car doesn't have them, don't go back to your dealer and complain because as mentioned the car does not come with them. Keep your dignity and just order them from one of the lovely online BMW parts dealers like Tischer and save a little money.