O. hamatus apparently does not occur in Victoria, so it is not included in the Moths of Vicroria visual key based on antennae sahpe, structure and colour. iNaturalist shows several observations of O. hamatus from NSW. They all show straw coloured antennae:slightly bent with pectinations close up here:-(see second URL address for the precise image) https://www.inaturalist.org/taxa/1102771-Oxycanus-hamatus/browse_photos https://inaturalist-open-data.s3.amazonaws.com/photos/92422341/square.jpg
From iNaturalist this is a close up photo of O. dirempta male antennae: brown colouw, with pectinations. https://www.inaturalist.org/observations/25439451 Looking at the Moths of Victoria visual key (Part 6) and a blow up of the antennae of this sighting using Photoshop I believe the antennae are a beter match for O. dirempta.(male) and not O. hamatus,