Am I reading too much into his behavior?

There's this guy at my college that I'm not friends with... he's an acquaintance (if that), because we both helped out on a mutual friend's film set a couple semesters ago. But outside of that or things related to that (a few mid-production, then wrap-party celebrations and dinners), we haven't hung out or anything. I don't even see him around campus on a daily basis.
Then last semester one of my friends who's also friends w/ him stopped by my dorm for a visit, and as he was leaving he said, "Oh by the way, "Z" told me to tell you 'hey'."... but I had literally just seen "Z" on my way to a class a few hours prior, and he had greeted me then as well. Then the very next day as I was on my way to a class I was looking down at my phone, when I heard someone say "Hey (insert my name)" and I looked up... and it was him.

This semester (last week; we're 3 weeks in now), I was walking down the hall and heard someone say "Hey (insert my name)" and I turned my head and it was him waving at me. And yesterday I was on my way *to* the school as he was coming *from* the school; I was looking down at my phone so I didn't notice him until he said "Hey (insert my name)". And then just a few hours later when my classes were over I was on my way back to my dorm, and I walked past a classroom he happened to be in. I saw him, but didn't say anything since I was in a hurry, and he was talking to somebody anyway. I didn't even think he saw me back... but then like two seconds after I'd already passed the room I heard him call out "Hey (insert my name)". I just kept going.
So am I over-thinking this or reading too much into it? Honestly I think he must like me because it's like he's literally greeting me every little chance he gets and we don't even hang out or anything like that, and none of the other guys I know, even the ones I do consider friends, act like this.