WARNING: This page is about a different car, the 2010 BMW 535xi, 2009 BMW 535xi, and 2008 BMW 535xi. However, it is still accessible from the selected car via links, so may be relevant.
Series: E61
SI number: 1 07 04 (085)
Order number: 51 0 050
Support for rear lid
Fig 1: Identifying Support For Rear Lid (51 0 050)