I know that in regards to the new Synchron Brass and Synchron Woodwinds, they both come with the respective BBO Libraries. So, yes, buying both the Synchron Woodwinds and the BBO Versions of the woodwinds would be redundant.
Typically what happens is that if you already own the BBO libraries, there may be some discounts when purchasing the Synchron libraries. If you check out the "Info" tab on the product pages, it'll usually show what kind of discount you get towards the Synchron libraries! I hope this helps!