No, they aren't very hard, they just require patience and keeping your eyes open. The only reason people thought they were hard is because they were impatient, because some of the gun battles are quite elaborate and drawn out, moreso than any other game I've played, even moreso than the other two Uncharted games, for the most part.

But I hardly ever play shooters and can't aim for crap, I had no problems, so I don't think you will.