True. But I don't think that'll be as interesting as the photos of his injuries. We know the doctor treated him for a broken nose (and we know that Corey did not speak to Zimmerman, and did not seek any evidence relating to his injuries beyond what might be in the SPD investigation file), but in this day of non-readers and reliance on a "visual message," the photos of Zimmerman's bashed face will do more to turn this case right side up than any other piece of evidence.
I also didn't mention the forensics relating to powder residue on both Martin's and Zimmerman's clothing, and powder burns on Martin's clothing.
I’d think the forensic (gun powder)and autopsy would settle the case. OTOH reports can be manipulated. Pictures ARE worth thousands of words.
There's also the matter of chamber of Zimmerman's gun being empty, which raises the possibility that he may have been shot during a struggle for posession of the gun.
I assume they also have, or will have the lab work on Trayvon's blood chemistry which may yield some evidence.