The pastel x black pastel makes a black pewter.
And as far as one being labeled the other... Some black pastels look like classic black pastels. Some look line cinnamons.
Some cinnys look like a standard cinny, others look like black pastels.
http://ball-pythons.net/forums/showt...n+black+pastel this thread is a GREAT example of how similar the two morphs can be.
I believe that the lesser and butter, and cinnamon and black pastel are two different but compatible strains of the same mutation.