Does he like me?

Ok so I work at a Chick-fil-a in my town and this regular customer comes probably 3-4 times a week. He's a junior, I'm a senior and we know each other because we used to ride the school bus together. Whenever he pulls up to the window which is what I do, he instantly starts smiling and it makes me smile and like its a smile that is completely irresistible. He has a gf but like does it seem like he likes me? like Ik he's just smiling but just the way he smiles you know?