That is good news
There are breeders and breeders. Some people breed hamsters but aren't actually "breeders". A true breeder will know the ancestry and pedigree of the hamsters and they will be pure Winter White or Pure dwarf Campbells. If it's just someone who calls themselves a breeder and doesn't know the ancestry and pedigree then they could well be hybrid dwarf hamsters - which can look like either Winter Whites or Campbells but still be a hybrid of both species.
The only real difference to you, in having one is a pet, is hybrids have more specialised requirements for diet as they can be prone to diabetes. So a sugar free hamster mix is a good idea. Burgess dwarf supahamster is a good option - I think Amazon sells it.