from what little i know about this work is - it all depends on so many variables when the floor was polished and who did the grinding and polishing. ie preparation.
some builders will use a power float or a steel trowel, and consider it a polished floor but professional floor polishers do far more than that, and charge for it quite rightly.
come back with your question when you know exactly whats going to be done to the slab - is the conc already down and well mature?