Yes, yes, some, yes.
Expert analysis of the audio proves there were at least 3 guns used in the attempted assasination. Possibly 4, including the shot by the SS sniper that killed the perp on the roof. Shots 1, 2, and another definitely from the 20-year-old. Others from a secondary gunman possibly from inside nearby building.
With the timing of everything, it makes more sense that shots 3 - 8 were from Crooks. They were more on the wild side, and would have allowed time for him to recover from muzzle sweeping the cop in the opposite direction of the shot and get his position.
If he recovered and got off shots 1 - 3 then he definitely was good enough for the high school rifle team unless he'd been practicing an awful lot lately.
Too many things happened that would require more life experience than a 20-year old possesses.