yea it seems that they like to leave hints for future games in all the generations. there are probably some in diamond and pearl right now that we dont even notice.
i was recently playing my ruby version the other day and in the place where you get your fossils rsurrected there is a guy that says that he is working on a machine to see pokemon's dreams.... if they did the remakes of these games i wonder if he will have finished the machine and we will be...