McLaren Mercedes is today debuting it's temporary 2009 front wing on the heavily modified MP4-23A. Pedro De La Rosa is running the new configuration which is also lacking barge boards but still features an old rear wing.
Race driver Heikki Kovalainen on the other hand is running the MP4-23K, the KERS test car that is still equipped with 2008 aerodynamic configuration.
McLaren's solution is visibly more elegant than what BMW Sauber is currently running. The front wing flaps are curved, most likely to get more air in between the front wheels, rather than hitting them. BMW looks like having the same idea but have their splitter do it in a different way.
Also note the the test car is sprayed with green oil paint to mark the airflow around the car's bodywork. This method is often used to verify simulations from the wing tunnel and CFD tests and indicates McLaren's desire to clearly understand how the new front wing influences the car's airflow.