No.
He should have a new trial.
One man was hit and down when he shot him again. That is acceptable if the man down was still trying to attack him........and had the capability of doing so, but I don't believe both those things are possible in this case.
The three requirements for use of lethal force are intent, weapon, delivery system. If the guy was already fleeing, and shot and down, he was probably missing intent and delivery ability.....
That said, anyone immediately under violent attack deserves some benefit of doubt, IMHO.
The problem appears to be with the judge's instructions, in which it seems he instructed the jury self-defense was not a possibility.
Oops.
Honestly, just from the little we know of this, he probably should be found guilty again......