He's a cutie, I was actually wondering about him or her lol.
How much is he? Was he bred for work, or AKC conformation?
I'm not familiar with the Aussie registries, but I know of ASCA (American Shepherd Club of America). I'm guessing that's the main working dog registry.
For border collies, we have ABCA (American Border Collie Association). Pretty much, (in case you didn't know,) working dogs with the ABCA registration can get AKC pedigrees, but it can't be the other way around. Dogs bred for AKC conformation don't have the same temperament or instinct as dogs bred only to work livestock. So they can't be registered as working dogs.
Edit: here, almost all Aussies are docked. There's a guy that breeds them but his all have no tails. And all of the ones I've seen have bigger butts and tummies than my border collie. So it makes me laugh that they assume.