http://cgi.ebay.com/ebaymotors/Mercedes-Right-Headlight-Lens-E320-E420-E300D_W0QQcmdZViewItemQQcategoryZ33710QQihZ019QQitemZ290069697418QQrdZ1

Before you buy the lens, see if yours have been glued where the clips are on the gray surround. There was a Factory TSB that had the dealers glue these so that no one could change the lens to Euro spec lens. The dealer was supposed to do this on any cars that came in for normal service, but very few ever got done, but check to make sure .
If they are original, you can just unclip them as Steve mentions..the plastic surround and gasket comes with the lens.