No, the Effort Ribbon has been removed since you can't obtain ribbons in Black/White (I'm not sure if the Champion/Battle Tower Ribbons are still obtainable however). You can still check if a Pokémon has all 510 EV's though, by talking to a woman in the house behind the Opelucid City Pokémon Center. She'll say "Your ____ has put in a great effort!" but won't give you a ribbon.