Also the problem are not JR or JS, but the way open shots are simulated. Open shots should have a higher chance of going in, but it appears that team defense is what determines the success of an open shot.
Yes, yes, a million times yes. Did I mention yes?

I still remember a SG I had (Jack Poirier) who consistently over a two plus season span had a higher FG% on contested jump shots vs. "open" ones. I don't believe I ever played him out of position (so always PG, SG, or maybe SF) so it's not a case of lighting up the three skill donkey big men, either. And he was my best pure jump shooter pretty much all of that time, so it wasn't like it was just a guy who wouldn't shoot unless given a tremendous matchup.