I think they are the same species, all males judging by the long filaments on the antennae. Moths of Victoria part (Part 6) provides visual key to Oxycanus based on antennae shape and colour for males and females. Only O. sylvanus and O. janeus malws have antennae where the lengths of the antennae filaments are markedly different either side of the midrib as we see here. In the key O. silvanus appears yellowish wherease O. janeous look more reddish, but i'm not sure how relaible that is.
Your second photoe clealrly shows reddish antennae with markedly long antennae filaments one side so I'm having difficulty in ruling outPO. janeus, although I'd like to hear a secomd opinion on this!