A few have asked me how to tell the difference.
We know that the early bikes up to 2010 sometimes had leaky valve cover gaskets. The new style gaskets seemed to have cured the problem. For the DIY'rs checking their valves and wondering whether to spend $75 on a new one, here's how you tell:
Old style on the left-just a bolt and rubber gasket. New style on right-bolt, concave washer and rubber gasket. The bolt remains unchanged but the added washer gives another .5mm of "crush" and helps prevent the gasket squishing out sideways to better seal things up. As far as I know, the actual gasket remained unchanged as well. Just remember to put a dab of silicone in the corners of the half moons for added luck.
My 08's is leaking so I cheated. Tossed the old bolts and installed the new style without removing the valve cover. Meh, we'll see what happens.