My understanding is yes, you would get both. Check out this previous thread: http://talk.collegeconfidential.com/suny-buffalo/1762552-free-tuition-stem.html#latest. I would definitely call UB (financial aid office?) to confirm that, though.
We’re currently thinking through whether to do it (incoming freshman). If everything falls into place, it is compelling. The tricky part is determining what happens if you don’t fulfill the agreement.