The only thing you needed to change is the if clause is the equals check to use uuids and not id because newly created items have no id before they are saved but do have a uuid .
You will still need the  conceptToValidate.getConceptId() != null because the reason it is there is to ensure that when you are saving an existing item, the code doesn't end up thinking it is a duplicate because getConceptMapTypeName will always return it if you pass in an existing item's name