Sorta... It could be the toys 'r us thing, but from what he was saying, it sounded like something else:
With the true arceus, you can go back to the sinjoh ruins, and get another of the dragon trio. The old man who notices the arceus won't show up, you just appear in the ruins when you go through the ruins of alph.
Either that, or he did
read about the TRU thing and his semi-overactive imagination did the rest.