Register item without linking it to mint and then ask admins to register them as a mint, if you have evidence that they minted it themselves and did not just order branded set from other vendor.
It is easier to justify system change, when existing item in catalogue needs it.
Highly unlikely that this wasn't made by a third party. But there is no public information about the mint so you would need to ask them directly and hope that they are willing to give you an answer.