I'm sorry I put wrong they are 23kt gold, and I don't see a mark but here is a site relating to them. http://bulbapedia.bulbagarden.net/wiki/1999_Burger_King_promotional_Pok%C3%A9mon_toys
the cards were made with a pokeball. I got extra's so i do have worry but do you gave the small paper saying it 24k gold plated charizard playing card?