I would say it is definitely not too late to call. You just met him yesterday after all. I would think that, if anything, today might be too early to call. If you wanted to be really casual about it (since you're not sure you're really interested) you could call him later in the week, like on Wednesday, to see if he is going to the bar on Friday. Then maybe you could hang out a little more so you can see if you're interested enough to go on an acutal date.
Unless you just want to hook up hook up. Then you can call any time.
