Sure, it's possible u will dream about someone u like, but that doesn't mean everyone u dream about is someone u like. I've dreamt of people I dislike tremendously... and also of people I only met once.. of just saw and never met, etc.
Technically, our minds cannot make faces, so every face in our dreams is of someone we've seen before (in the streets for instance). I don't know if thats true, but I doubt dreaming about someone means u like them. Maybe in a certain context it might. zoek for "dream dictionary".