Hi Bulionz
Sorry this is long, but everyone's just putting up a few bits of info or opinion and it's probably not answering your questions.... so here goes mate!
The laws on breeding, microchipping, numbers of dogs you can keep etc. vary from state to state. Best place for information is your local council. If you look on your dogs' tags the name of the council should be on there, or maybe ask Mum or Dad. Your council probably has a website with info on dog registration, care, the local laws etc., so you can get some info there. They might have a link to the state or territory dog management authority which will once again have heaps of info.
As for the prefix thing...
Each state has what used to be a kennel club. Here in South Australia it's called DogsSA, previously the South Australian Canine Association. All those state and territory clubs or associations are affiliated with the ANKC (Australian National Kennel Council). When people who keep a new breed of dog want that breed recognised they have to apply to the state organisation. If the state organisation accepts the breed then the people who have those dogs submit those animals as being foundation stock. So with our border collies when the ANKC decided that border collies were a formal breed (as opposed to being black and white sheepdogs) the people who wanted to show their dogs as being what a border collie should look like submitted their dogs as foundation stock. The border collies bred by a farmer that work sheep brilliantly might be just as good or better than the ones put up as foundation stock, but once that foundation stock was accepted the "studbook" was closed. So in the case of my dumb but gorgeous Bailey he's a predigreed border collie, and his prefix is Busheyhall, so his registered name is Busheyhall Bluesboy. Gypsy, my intelligent and gorgeous border collie is not accepted by the ANKC people as a border collie because she's not pedigreed, but the farmer who bred her called his business Honeyvale, so she's said to be from Honeyvale lines. As well as the ANKC register of prefixes and pedigrees there are also various registers for working dogs, and farmers or stockmen who are looking for a good working border collie would look for a dog from good working lines.
Where the lines get blurred is that there's a hereditary brain disease called ceroid lipofuscinosis (CL) that some border collies carry. It's a nasty one where the dog gets a buildup of stuff that's like cholesterol in the brain, and a pup can seem perfect but then when it gets a bit older (around 1-2 years old) it may have seizures, loss of coordinated muscle movements, change in temperament, and sometimes problems with eyesight. These dogs don't usually survive past
26-28 months, and unfortunately there is no treatment or cure. The good news is that only about 3% of border collies in Australia have or carry the gene for CL, but that doesn't help if your pup is in the 3%. The ANKC breeders keep track of the family tree of every dog, so when they discover CL in their stock they can just stop breeding from those dogs. If you buy a BC from a registered breeder (one with a prefix) then legally the border collie pup you buy SHOULD be guaranteed free from having or carrying CL. With any other border collie you don't know. CL is very rare, and the vast majority of bc's are free of the disease, but if you want to be 100% sure then you go with a registered breeder.
Apologies again for the length of this post, but I think you've got more info now.