It should be as Immutabilis is one of the few Aussies that can be dried. If it is wet and refrigerated it should be fine as long as it does not smell rotten.
It likes warmer temps to germinate than Brachyceras so be prepared to offer 80F + temps to get it going. I have started it from seed before, it just needs a bit more attention if you are doing it under light, Outdoors it will germinate fine but if you want a blooming size plant by early summer I would start it now under light indoors.
Cheers,
Sean