that's because the current sprites are extracted from PO(br)'s client, thats why they already have crystal onix and elder charizard.
anyway, red gyarados is from johto, which is 2nd gen, which won't be released just yet.
Will we be able to fight with eevee and its evolutions and ditto , porygon those pokemon that theres no spawn for them in PO like hitmonlee , chan etc etc