Sometimes what you're looking for may be listed as a spare part rather than an accessory.Well that was quick- Tesla Australia response:
“At this stage we’re not sure exactly what parts and accessories will be available or when but we are looking into it and are hoping to launch to Model 3 parts and accessories locally in the coming months.”
I bought the red Tesla Euro adapter, 32 and 20 Amp cables for my Model S UMC. They fitted nicely in the UMC's bag but not with the UMC in it.
When I was at Alexandria I asked them about it and they found the UMC bag listed under spare parts not under accessories, so I bought one for the adapter and cables so I have 2 matching bags in the boot, one for the UMC and the other for the Euro adapter and cables.
You may find the Model 3 Wheel Caps are a spare part rather than an accessory, so a Service Centre may be able to order them for you.
I'll try and remember to ask when I take my car in next week for the CCS2 upgrade, presuming they don't cancel it like they have done to others.