Well, yeah. I mean, there's nothing physically preventing someone from being more usual than unusual. Humanity isn't just a bunch of chaos where there are no consistent viewpoints across majorities or things most people have in common.
In the sense of 100% normal? Technically, it's possible. There's nothing physically preventing someone from being completely usual. What that person would be like? I have no idea beyond the fact that every detail of them would agree with what the majority is. The problem being A that what is 100% normal changes ridiculously often and that B the odds of it happening are also ridiculously low.
In fact, while I'm thinking about this, I'd go as far as to say that we have a tendency to use the word normal wrong. See, applying the word normal to a person is like, a giant generalization. The word normal should ideally only be used to describe specific things, not general people. In essence, the person who thinks they're cool for doing something abnormal is just as normal a PERSON as the person who does the normal thing. What I'm saying is, people who do abnormal things are not abnormal people. We as human beings just share way too much in common when you look at it from a literal point of view to be considered abnormal no matter what we do.
And we also probably use the word abnormal or weird wrong. Like when someone calls someone else weird, what they probably meant to convey was "What you're doing is weird" or "What you did is weird". You see, calling someone weird or abnormal is simply a ridiculous concept when you think about it.
Oh, and doing something abnormal is not necessarily wrong. Though in some cases normality exists for a darn good reason. For instance, jumping into a volcano is totally something you should identify as bad based on what others think or say about it, not through personal experience. So it's really something the individual needs to be careful in deciding whether something is normal for a good reason. Lots of things /are/ normal for reasons, but sometimes they aren't. There's usually a reason for why there is no reason for normality, such as the reason disappearing, but people just continuing due to force of habbit, but hey.