I'm basing that purely on common sense because there's no artistic or technical benefit in making the (checkerboard) image of a lower quality on a 4K screen than on a 1080p.
I can't say that they aren't doing that as they haven't specifically said that but the reason they haven't is surely it is absolutely common sense that they wouldn't even think about doing such a thing unless there is specifically a version that renders at a lower resolution, like Tomb Raider, to free up resources that can be used for other benefits.
I do apologise to everybody as I seem to have taken over this thread and I really don't want to do that but there has been misinformation on GAF so it's entirely understandable that people keep posting it.
You'll all be please to know that I'm going for hike/scramble/climb now so you'll all have peace from me for a few hours.