I went though this years ago. The dealer insisted they gave me the right and only code that showed up on their normal computer search. I finally found a tech at the dealer that knew there where multiple codes. The dealer finally sent a fax to BMW headquarters and they sent back 3 possible codes. For some reason, some models have 3 possible codes. The dealers normal search gave the wrong code, but one of the others did work.
KEEP AFTER THEM until they give you all the codes for your serial number from BMW not just their normal computer search!
Once you get the code, write it down in several safe places.