Yes. And indeed, he invented it, in the late 60's.
The shot was executed for the first time in 1974 at the courts of the Club Obras Sanitarias of Buenos Aires in an exhibition match against the French player Wanaro N'Godrella. In a official match, the shot was executed by Vilas for the first time in 1975 in the Indianapolis tournament on clay, against the Spanish Manuel Orantes. I don´t remember if I heard some time that he made it in a previous game, but anyway, it's true; and you can see a text of his book "Quién soy y como juego"(1976) in which he describes how he discovered that shot:
http://www.facebook.com/notes/tenis...rgio-pedernera/la-gran-willie/108799115836741
I will try to translate it to english, It´s interesting to make a thread!