The law doesn't care about licensing, there are just 2 groups of printers - those that follow the law and implement effective blocking technology and those that don't.
If BBL sells an open source printer that allows someone to trivially bypass proposed mandatory blocking technology, they'll be fined and held liable for any crimes that result from guns printed using their 3D printers.
So BBL, as open source as they might want to be, is not allowed to sell such a product.