Looks like there's a few people in the edit history in the release group - I would leave notes for them and see if you can ask if anyone can check.
Keep in mind that MB sometimes has bad information, particularly with DiscID's (because they're easy for users who don't care about specific editions to save to the wrong version, and also because in the past we stored DiscIDs with release groups and at some point migrated them to ALL releases (pretty sure?)). So if you have a copy in hand and the edit history is suspicious/non responsive, I think it's sometimes ok to throw out unverifiable information.
But that should be a last resort
edit: scans are definitely awesome, because then you could check and make sure that your copy is actually EXACTLY the same as the other one. Will help the next person who comes along immensely!