You will see in the HCW when you run it what it is configured for but there is a couple of ways you could confirm what is currently configured:
In Exchange Management Shell On-Premises you can run Get-HybridConfiguration and look at the features to determine Minimum vs Full Hybrid. Then you can look at Get-MigrationEndpoint on Exchange Online and see if the endpoint ends with resource.mailboxmigration.his.msappproxy.net then Modern Configuration of HCW has been run in the organization. You can review the logs located in %APPDATA%\Microsoft\Exchange Hybrid Configuration and search for Mode and Migration Endpoints in the logs to determine if you have Minimal or Full Hybrid under mode and if the endpoint ends with resource.mailboxmigration.his.msappproxy.net then you know that Modern Configuration of HCW has been run in the organization.
