Clarification on same Pokemon with different rules

[Hokiecow]

I've come across Pokemon cards that are identical except their attacks. Some have the same name and picture but different attacks and some have different pictures and attacks but the same Pokemon name. I assumed that both cards are legal. I can use both cards in a match and I must use what ever rule is for each card.

Then I read the rules for legal cards and Reprinted Cards. Both rules basically say the same thing; that the latest print of a card has to be used if it's significantly modified. In the example above, the have different attacks, that seems significantly different. So in does this apply to my example above? If so, how do I know which Pokemon card has the latest rules that I must apply to all similarly named Pokemon?

http://pokegym.net/forums/view.php?pg=xpdformat
"If you are playing a card that has had text significantly modified in later printings, you must have a copy of a card with the most recent printing outside your deck available as a reference for your opponent. In a few cases, if a card has changed dramatically from it's originally named version, the old version is not allowed at all."

http://support.pokemon.com/FileManagement/Download/285237e1e815473dbac38d3a368f84a2
"From time to time, cards printed in previous expansions are reprinted in a new expansion. In most cases, the mechanics of the card remain unchanged, though the wording may be slightly altered for clarification. However, in a few rare cases, the game play text of a card is significantly modified. Should a player choose to use an older printing of a card that has had significant text changes, the player must have a local-language version of the card with the most recent text revisions, outside of his or her deck, for reference."

 

[PokePop]

I can see how that can be unclear to a newcomer.
That rule doesn't apply to Pokemon (the creatures, not the overall game).
Trainers and Energy are unique cards. Any Trainer or Energy with the same name is the same card.
If an older Energy or Trainer was printed with different text than a new released version, all of the old cards must be played by that new text. There are a couple of examples where the change is so drastic that the old card is not playable at all, but those are very rare.

Pokemon are different. There are many versions of the same Pokemon, sometimes multiple versions in the same set.
Here's an example of that from the most recent set:
[gal=56327]Articuno[/gal][gal=56328]Articuno[/gal]
Since both of these cards are from the same set, obviously "most recent printing" doesn't work for Pokemon creature cards.
No, for a Pokemon to be considered a reprint, all of the game text must be virtually identical. Not word for work, but identical game meaning.
For example, here are two cards that fit the "reprint" rule and when the new card was reprinted, original versions were allowed in tournaments at the time:

[gal=41019]Charizard[/gal][gal=45699]Charizard[/gal]

And, more importantly, here is an example of an "almost" reprint. There were some difference, so the original cards was NOT allowed to be played in current formats:

[gal=50659]Sneasel[/gal][gal=46659]Sneasel[/gal]

Note that the Weakness is different. That's all it takes to make it "not a reprint".

And to further clarify, since the examples I game used cards with similar art, the artwork doesn't matter. Only the game text.
For example, these two cards are considered the same card for game purposes:

[gal=1174]Pikachu[/gal][gal=47598]Pikachu[/gal]

And finally, regardless of different versions of a Pokemon card being treated as different cards, you are still limited to 4 cards of the same "name" in a deck.
So, no matter how many different Pikachu cards there are (and there are a lot!) you can only have 4 cards named "Pikachu" in a deck.
Of course, you can have 4 cards named "Pikachu", 4 cards named "Flying Pikachu", 4 cards named "Surfing Pikachu"...