Hi eonman, the scratches are common in stone, they are most visable in the dark colors. They usually are from 2 things
if they are circular they are from the polishing process at the factory
if they are somewhat straight they are from poor handling
your fabricator probably didn't cause them but he needs to learn how to fix this problem before he sells the material.
I would suggest he take the next NSRA
class and he will be able to easily fix this for you, if you. haven't made final payment, I would insist it is fixed to your satisfaction or it is replaced. the
class would cost him less than replacing your tops and you won't have to deal with the inconvenience