BillyMayfair: why are these - a level 45 ball - only available to Legends + players?
This I can only guess, it happened before my time.
In August 2010, "new" WGT Levels were announced and later introduced, look at the News from Aug 19, 2010. Before, equipment was primarily accessible by tier - see the Clearance Sale ad there.
My best guess is that those Legend balls are a remainder from then, though the type of Callies was introduced much later, as a replacement of older balls.