The reason the part number doesn't show up there is because they're using a 15-month out-of-date catalog (the opening banner says "New Updated 2/09 Catalog").

Penske operates a BMW-sanctioned web catalog here, though you don't want to buy from them (at least not at those prices, which are US list).

Tischer has an online catalog here which offers discounts.

The final arbiter of what is and isn't a valid part is the live BMW ETK. Here is a 3-page snapshot from the live system as of this morning.

Looks like the list price is $100 with a core charge of $500. Which is borne out by the description of the part in the BMWNA ordering system (not the ETK): "EXCHANGE DVD DRIVE ASSEMBLY". At the moment, the 65839232059 drive (non-exchange) is still available for $817.09. But if you look on page 3 of the PDF I linked above, that part has been superseded by the 65839237706 as of March 29, 2010 so inventory will not be replenished.