It could have been a ricochet from the first shot miss or a fragment from the head shot. Neither is provable and either is possible. Now why don't you give us a plausible explanation for Tague's wound that wasn't from a shot fired by Oswald.
A direct strike by an intact bullet would have left noticeable damage to the curb. It also would have left copper residue on it. As it is, there was no visible damage to the curb at all and no copper residue on it. All that was on it was a lead smear and a trace of antimony.
