Actually theres no black part at the wishbone in the pic.

And Wishbone seatstays is not something Trek has just made for the P-R bike, Trek has made several standard bikes with wishbone, for example Trek 5500, 5200, 5000 etc. It would probably have been too expensive anyway to make wishbone seastays just for P-R. In fact the SPA bike is just a standard production Trek 5000 bike with some of the wishbone cut out: http://www.cyclingnews.com/...atures/hincapie_bike

The bike with the black SPA Hincapie took to the podium is not the bike he rode in P-R.

But actually It seems Hincapie did ride with SPA, but definately not the black one as he took to the podium.
Here's some pics of the bike Hincapie raced in P-R:




http://www.tdwsport.com/...1734.jpg&thumb=0

http://www.tdwsport.com/...1747.jpg&thumb=0