Do different cards with the same name count as the same card for the purposes of deck building? For example, can I pack 3x Catelyn Stark (Core) and 3x Catelyn Stark (LoW) in the same deck?

P.S. Can one Catelyn be played as a duplicate of the other?

Deckbuilding rules say you can only have 3 copies of each card by title . Versions - or card types - have nothing to do with it. You can have a total of 3x "Catelyn Stark" cards in your deck, regardless of the version. Note, of course, that those 3 can be any combination of all the versions available.

And yes. You can use one version to dupe another. Even if they are different card types.

Thanks for the clarification. I don't think the core rules actually specify that the distinction is made by title. The rules just say: "Your House deck...may not contain more than three copies of a card."

Look in the FAQ. Page 9.

Ah got it. One more somewhat related question: why does Valar Morghulis specifically say "limit 1 per plot deck?"

because there have been in the past some cards that allowed you to have more than one of a plot. It was during the CCG days but the text was reprinted on the LCG versions anyway. http://agot.dbler.com/index.php?view=card&arsenalid=18915

Toqtamish said:

It has less to do with the fact that there were cards that allowed you to have more than 1 copy of a plot and more to do with the fact that at one time, the rules allowed you to have more than 1 plot. The "limit 1 per deck" plots are reprints from that time.

It's not like Valar was originally limited to 1 per plot deck in 2003 in anticipation of Princes of the South being printed in 2008.

Alright. That was way before my time. Interesting rules difference to be sure.