That's true but only for the magazine. The gun itself was inconclusive
But like I said, DNA wouldn't be enough on its own to convict or prove innocence since it'd just show that he handled the gun at some point. Not necessarily fired it. Plus, he could've wiped the gun, it could have been contaminated during investigation, or the DNA could have degraded through other means
It's not that we disbelieve anything the defense says, they haven't been able to substantiate anything to clear him. So that's on them not us