A little bit, but that doesn't mean it's a bad thing.
Guys think that pretty much everything girls do is weird, and so past a certain age, most of us give up trying to figure you all out.
He might find it a little awkward to call you, since he doesn't really know you. Hopefully he at least knows your name, or you wrote in the note.
Most guys are fairly non-judgmental people, so you shouldn't worry about him thinking it's weird or not. I doubt he cares about that. He will call you if A. he's interested in you, and B. he's not too shy to call a girl who randomly gave him her number.