http://www.ebay.com/itm/1921-S-WALK...28?pt=Coins_US_Individual&hash=item4610954838 I see the 6 lines coming out of the sun, reaching to the blouse. Maybe there's 7 and the 7th is worn off, i don't know.
I think it's most likely authentic, but be careful on bidding. That gouge on the obverse knocks the value down considerably. Save your money, and buy a nicer example.