I would also raise more pre-flop - probably 120.

Usually I'm pretty tight at the beginning of a tourney, but I would make this call. I think the overbet is a read in of itself - I think you are ahead.

What buyin are you playing at? I've found that at the beginning of low buyin tournaments, there are some very aggressive moves like this that are not always founded - this is a good time to demonstrate people shouldn't screw around with you, even if you are tight. While this is not a read on a specific player, but perhaps the game. Not something I would rely on heavily, but perhaps consider.