Well if they sold out, wouldn't the units available and sold be the same? Unless they are selling units that don't exist yet. Apple does this too, they say "We sold out in x hours" and neglect to say how many units they sold. That info does come out later after the headline wears off.
You are missing the point. If they sold out of 10 units, that is not impressive. If they sold out of 10,000 units, that is pretty amazing for Australia.
Apple usually doesn't say they are sold out, you can just infer it from the availibility dates on the website (e.g. if the store says shipping in three to four weeks). If a product is successful (and all their big products everyone cares about have been, so they have always been reporting numbers on iPhones and iPads) they will usually report a nice round number after the opening weekend (like "We sold three million in three days!").
They will say when they are supply constrained, but that's during their quarterly calls when being supply constrained is properly interpreted as a more negative than positive thing.
