They will be different than the June's one. This is so that people don't cheat of course and get hold of the Jan paper and get the answers. The same is for any other paper for other exam board/subject/level.
As for difficulty - this is normally how you would feel. If you can answer the questions and think you are right, then you could have found the paper easy, whilst the opposite is hard. Of course people have different opinions on the difficulty of the paper. But that shouldn't matter in terms of the grades - its how people do in the paper.