When you say certified true copy it means that you had the original photocopied (e.g. transcript of records, diploma, etc.) and usually there's a dry seal and a signature from an authorized person in an office where you got those documents. The authenticated documents on the other hand, like the ones coming from DFA for instance they are the ones who make sure that the ceritified true copies of the documents are indeed correct and the authenticating officer will issue you a certification bearing the signature of the officer, a seal and a red ribbon. Also, a documentary stamp is usually visible on the certification. I hope this helps you.
I have mine authenticated by DFA.