Yes and no. The events that night are already a matter of record verified by the forensic evidence. He doesn't need to say another word about those events. And even though it is not admissable in court, he did take and passed a lie detector test. So the statements that he gave that night will have their own credibility.
The problem with all the other evidence is that for the most part it corroborates Zimmerman’s account only to the extent that it does not contradict it. The only living witness to the shooting and to the start of the fight is George Zimmerman.
Self-defense is an affirmative defense, so his prior statements will have to be entered. Whether he is testifying live or his words are being read from the record, it’s still his word and credibility on the line, and this incident does not help his credibility.
This was a totally unforced error that will make his attorney’s job more difficult, i would think.