Yes, it means the witnesses on scene were all correct to say he had been shot (or shot at) at while running away. Many tried to paint the witnesses as liars, but the sounds do match their reports. Some of the early volley of bullets had to have been fired as he was running. It's likely his arm was grazed while running away (arms down) rather than the other possiblity- face front/ arms up for his inner arm wound.
I do wonder if they can hear anything earlier- the bullet being fired in the car? I'm not sure the chief confirmed that happened- I thought it he had only described a struggle and it was unclear to me if Brown was in the car, or just his head and arm, as described by most witnesses. Also wondering if they will ever be able to know how many shots in total were fired by looking at the gun- or if some of those shots are stray bullets that are gone forever?
I think that is what is going to be crucial, if there was no struggle for the gun, then he shot a fleeing suspect in the back for no justifiable reason. OW needs us to believe that struggle over the gun happened, or his career is over. I also think shooting an unarmed person in the back is excessive force either way you slice it, but that OW will not be in trouble unless they can prove somehow that Brown was not reaching for his gun.