YES.
no they don't add Pokemon into your pokedex there
u need the national pokedex!!!!!!!!!!
You have to battle them.
Just go to Pokemon platinum central and click on pokedex and it shows you where to battle all the Pokemon in sinnoh.
you must have seen them in the battle frontier
If you see a Pokemon in the battle frontier you have not yet seen, it will not record it. The only way you can add that Pokemon to your pokedex is if you see it outside of battle frontier.
you get the sinnoh pokedex from professor Rowan afteyou battle the starly with one of the Pokemon in the bag and say yes to the professor and you get the Pokemon and the pokedex.
yes you see them but it does not go on your pokedex sorry
first beat the elite four and champion. next get to every where on the map third beat the battle frontier.fourth get the national pokedex.
you have to cheat and use the action reply and you will get the whole national pokedex or you have to go to the battle tower and beat it alot.And it depends on which game it is i just told you for diamond/pearl.If its platinum go to the battle fronteir.and one of the places should have bulbasaur {aka Pokemon #01} in it.HOPE THIS HELPS!!!!!
this question is worded weird but if your question is "where do you get all thePokemon in Pokemon platinum?" then the answer is to battle every trainer in Sinnoh.
first you have to battle with every pokemon like i did! it took me a long time but i did it on platinum i also have all legendary pokemon