Yep, it's not significant whatsoever. It's actually probably one of the most common things that can happen. First of all, the person can be someone you saw while walking in some city and you subconciously take notice of people's faces, in a movie, in an advertisement, anywhere! But it's not as if your mind can't make up a face. Considering, if you're say, 12 (just guessing a realistic age), then you will have been seeing your own face, other people's faces, and everything for about ... ,well, 12 years! It's called a dream character.