On yeah it's insane to think they planned for him to get grazed in any version of this. Seems like the most plausible version of the "it was faked" theory is that the dude was supposed to be there, get off a shot and like hit something nearby at most and Trump getting injured at all was a total accident.
But yeah I'm only talking hypothetically about the theory. I agree it's way more likely that things just shook out like you said.