better yet, use an allen key to take the radio out yourself, note down the serial number, go to any CS of any bimmer dealership, tell em you want the code and give them the number. That way they dont have any excuse to charge you for anything (not that they will charge you for pulling the radio out themselves but just to make sure).
edit: allen key works on the first generation E36 models so if its not that same radio then i dunno how to pull it out lols.