Currently OpenREM uses a combination of several tags to determine a unique system.
In RDSRs a "Device Observer UID" is present, which uniquely defines a system. I would suggest to use this UID if present for identifying a system. This UID is independent of the sometimes changing tags that currently are used.
In practise this UID can be used to automatically set the Display Name if the UID is already known in the database, but the data has a different combination of currently used tags.