Thank you for those caps!
That’s a good comparison between what I’m seeing in the test renders and what’s on that print. That grain is much more fine, but also more tightly packed in the frame. There’s an even-ness to its dispersal across the image (which is backwards, I guess, the image is being dispersed across it, right?) Whereas the artificial grain being applied seems to be rougher (and larger) and is less dense, so maybe that’s why I’m reading it as digital/color noise instead of grain?