NO, the scumbag was warned that the dog would be sent in and the dog handler in most cases is close at hand. Aiming at the dog is no different than aiming at the human handler that will be nearby. If there were no dog and the cop approached him gun drawn would he have had the right to shoot at the cop holding the gun on him? Fire a weapon when surrounded by armed police and expect to die, better him than one of the police.
There's clearly no probable cause in this case, and he wasn't even sitting in a parked car so that the cops could claim "he tried to run us over". They sent in a dog and shot the guy ~ for what crime?