Is possible to add any custom parameters you like. As long as is not a configuration key for the transport invoker, it will be ignored by remoting.
The NetworkRegistry fires a org.jboss.remoting.network.NetworkNotification when a server is discovered. The NetworkNotification includes ServerInvokerMetadata which gives the locator uri and array of subsystems. Don't know if subsystems would be enough of an indicator or not.
Could make code change so could also include the configuration map passed to the server invoker as part of the ServerInvokerMetadata included in the detection message. However, am concerned about allowing free form map for this type of thing as if contains a lot of entries that are not needed, will just be extra traffic on network serving no purpose.
I think that's the answer then. If remoting explicitly ignores unknown parameters in the locator URI, then that is probably the best place for me to put my own custom parameters for identification purposes.