You can only add a server manually.
However, the database only cares about the name of the server. It doesn’t matter what the serial number is. If this is all happening on a local network via bonjour, and the new server has the same server name that the old one did, then you don’t have to do anything, not even give them a new copy of the database (this is assuming you moved the Public Databases folder to the new server computer).
I have a suspicion I don’t really understand what you are doing here, so it’s difficult to accurately advise you.