Yeah, that's standard for theatrical projection, it's part of the system. You have those adjustable curtains that you use to crop the image, I think projectors themselves have gates that can be adjusted to crop too but I'm not sure about this. Whenever you see a film in theatre, there will be some mild cropping, and you get this in home video too (the 2004 transfer is the most open-gate transfer ever seen, so the difference seems more severe). The idea is that you don't want to see the edges of the frame or the side of the film or the white of the projector light, so you crop the sides; it's inevitable that you overcompensate a bit. This case looks a bit more severe on the sides, they may have had it that for another print that had a slightly different ratio and just didn't change it. For non-scope prints, the full negative area is used and it's up to the projectionist to frame the aspect ratio properly, so prints contain all the information that gets covered up in black bars on home video and it's the theatre that provides their own "black bars" (via the screen curtains or gate size).

I suppose it could be in the print itself as well in this case, I don't know if anyone has ever looked at IPs and prints versus the negative in terms of framing. I suppose when they are copied there could be a mild shift that eliminates picture information and the projectionist has to re-centre the frame. But I notice cropping in theatres all the time on scope prints and whenever I do I can see the "cropped" footage playing on the side curtains so its there its just that the projector and screen haven't been positioned 100% perfect.