This is correct. The "travel document" is a document issued by the Irish Government to refugees. It enables them to travel abroad and return to Ireland. Normally, refugees are not able to get a passport from their original country (as they're escaping from that country in the first place), so once they are accepted as refugees in a host country (Ireland in this case), the host country issues this travel document for them. The travel document basically says that the holder is not a national from the issuing country but is a resident in the host country. The travel document is the property of the host country. That's why INIS asks for it when refugees get naturalised.
If you are not a refugee, you do not need to send anything but the yellow form (properly signed by the judge), the fee (!!!) by way of bank draft/postal order and your original GNIB card.
I'm also taking my oath next week. Can't wait!!!