Since they've got bridge texting with 2.1, it's not that far off to think they'd have it the app for it ready for the 4G launch, so both bridged and native 4G users can take advantage of it.
And yeah, this is complete guess work.
They didn't want to demo anything big in regards to BB10 to take away from the 4G PB launch, but they gave everyone a little teaser of the interface. The 4G has been seen in the wild now for a while, but they've already acknowledged that the 'Wake Up' countdown in Australia is their marketing campaign.