Hi Chris
Temperaments depend on a lot of things - it doesn't follow that all black Cockers have the same temperaments just as it doesn't follow all blue roans have the same temperaments. If you are buying your pup from a reputable breeder who has allowed you to meet all their dogs & you can see they have happy, friendly natures, your pup should hopefully be the same. Other factors which contibute to good temperaments are how the puppies are reared & socialised. Reputable breeders take care to socialise their puppies, preferably by rearing their litters in their homes - puppies reared outside may not be so well socialised & may be more fearful once they leave kennels for their new home.
Jane