The official Japanese Pokémon website has revealed that as a grand finale event before the Pokémon Center Tokyo closes
will be distributed to players of Pokémon X and Y
as well as Pokémon Omega Ruby and Pokémon Alpha Sapphire
will be distributed on December 6th, 2014 while Keromatsu
will be distributed on December 7th, 2014. Both Pokémon will be Level 7 and their OT will be Hamamatsu-cho (はままつちょ).
When the Pokémon Center Tokyo reopened in Hamamatsu in 2007, its mascots were Pikachu, Hitokage and Pochama. With the release of Pocket Monsters XY in 2013, the logo got revamped and Pochama got replaced by Keromatsu.
The original logo for the initial Pokémon Center Tokyo in Nihonbashi featured Pikachu, Hitokage and Nyorozo. All three of these generational water Pokémon are currently featured in promotional artwork showcasing the Pokémon Center's move.