Yes, the new Preview Now works as explained in Aus as well. I saw it this morning, but I don't know how long it's been there - possibly yesterday.
The epub book I looked at had both the Preview Now button and Save Preview (which downloads into My Library on the web site and Kobo Desktop. The kepub version as Geoff explained)
So, that's another way of determining a kepub only book it seems ... if there's a Preview Now it's epub, if not it's a kepub.
Golly gee, I really would prefer they just stated it in writing.
Here's a pic of what I see.