Honestly, I would totally accept him for a purebred. Working Border Collies are NOT bred for looks, mind you! Half the people that meet Gonzo say "Oh, he must be part Border Collie!" erm... no... he is all BC, and has papers to prove that. His breeders could care less about appearance, they wanted working puppies, not pretty foofy puppies. You should always ask for proof of breeding of both parents, and registration with a reputable club.

I would never look for BC's in the paper, but that's just me! I think you'd find way better breeders, typically, by going to herding trials or agility/flyball trials, or asking for recommendations from good herding instructors. It's absolutely true that in most cases, a great breeder has people lined up waiting for their puppies, and for good reason! They're actively involved in exhibiting their dogs and their breed club, so there's no need for a newspaper ad for people to know about their litters.