I was able to successfully price match and use the B2G1 free promo to purchase MK8, SM3DW, and DK Tropical Freeze.
I picked up the games and asked to price match. They took me to customer service where she looked up the first game on Amazon then just asked me for the other two prices.
I never mentioned the B2G1 assuming the register would take care of it and it did. I'm not sure the sales rep even noticed that it happened.