I'll take a stab at this. You asked:
are these attributes stored in the file record themselves or in some type of central repository that determines what permissions each file has
AFAIK, your system determines how it treats anything it mounts. A good place to see this is in the /etc/fstab, which should be present across all Linux distributions. There's absolutely no respect by the local system for files created by the root user of another system--you can change and wipe them as easily as if you yourself owned them.
I'm no expert in the fstab, never had much of an inclination to learn the ins and outs, but therein is your answer. It lists who can mount what and when. And I think what happens is that if you're attempting to mount something that is not present in the fstab, you need super-user permissions, which is likely where the "root" group comes into play.
Hopefully that helps, don't take anything I say as gospel but I think this will point you in the right direction.
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