As you said, these files have a PMOC header, which makes them harder to use. Unfortunately just chopping that off with a hex editor doesn't really help, they're still unreadable. They don't seem to fit any of the specifications I'm finding online though, it might be some unique modified version.
I don't really have any ideas on what to do about it, but just figured I'd point out that they're not regular NCGRs.
I don't really have any ideas on what to do about it, but just figured I'd point out that they're not regular NCGRs.