Sounds like he was checking you out to me!
Congrats! It's a cool feeling.
I remember when I got checked out as a girl, it was few and far between. I never understood what had happened until later that day. One time a parked car honked its horn at me, so I went back over there and looked in the window thinking it must be a friend of mine. No, it wasn't... I asked, "Do I know you?" He's like, "No, just saying hello..."
I thought that was quite strange until I told people about what had happened. They enlightened me.