Welcome to BYC. Glad you decided to join our flock. There is definitely a Black Orpington breed (Black Australorps were first bred using Black Orpington stock), and although they are very uncommon in the USA (BAs are far more common), there are some breeders, and even a few hatcheries that sell Black Orpingtons. About the only difference visually between Black Orpingtons and Black Australorps is that Black Orpingtons are a little larger bird (when the Australorp was bred, size was traded down for an increase in egg production). Given the size of your birds in the photo, I think you probably do have actual Black Orpingtons. Please feel free to ask any questions you may have. We are here to help in any way we can. Good luck with your Orpingtons.