Pokémon Ranger and the Temple of the Sea Easter Egg - Pokemon DP Game Reference?

When team rocket find out about the treasure, Jessie says "Just think, soon we'll have all of those 'diamonds and pearls'" and I thought it was just a simple thing they say for treasure, but to confirm it, Meowth then says "Hey, thats a good title for a game", making this a reference for the pokemon D/P games, which manaphy is from, along with chatot.