It sure is. GZ told the police that he called out for help and at least one witness said that it was him. Under the scrutiny in a court room it is bound to become very clear what the truth is. If Zimmerman was the one crying out for help this whole case will fall apart.
Zimmerman’s injuries as stated in the police report are another aspect worth noting. As someone said here days ago, when police are called to a domestic dispute, they assume the person with the injuries is the victim and not the aggressor.