If I recall correctly, during the beginning of [*The Godfather*](http://www.imdb.com/title/tt0068646/) Tom Hagen is sent out to Hollywood to convince a producer to use an actor, when the producer balked, he ended up waking up snuggled up to his favorite horse's head.

Do we know if that implied threat actually worked? The wiki states that Woltz was unmoved until the horse head incident, but is there ever any indication that it actually worked as intended?