Hi roarmom,

the Sixt Station named with BMW are inside of a BMW retailer.
At these Sixt stations you will only get a BMW (OK, also a MINI).

If you want to get a BMW, choose one of these stations.

The best way is, as suggested by ulev, to make a reservation at the Airport and a second one at one of these BMW-Sixt stations. You will have a comfortable transfer to your Hotel and latest after the change of the car you will have a BMW.