Spat / rear wheel air diverter flap thingy. what rivets are needed?

Does anyone know the rivet parts needed to install a replacement spat/rear wheel air diverter/flap thing?

The spat is part 30 on this diagram.

http://ift.tt/1D0yffh



The rivet, part number 51161881149 is my best guess from the realoem diagram. But I really cant tell if that is the one for mounting the fender liner.



Some of the pics of the spat part show a single rivet, but 2 other blank holes. so I am not sure if I need 2 other rivets per side.



Thanks

for a 2003 540i M-sport.

Spat / rear wheel air diverter flap thingy. what rivets are needed?