The Azumanga playing cards in the sega UFO catchers that released in 2001, had a prototype version shown at the Sega Prize Preview Event on November 6th 2001.
There seems to be a few differences between the released Cards and the prototype cards. The released cards have a red color on the "NOW" card and a blue color on the "WAS" card which are both joker cards. The prototype cards instead have a black color on both cards, with the word "NOW" appearing to say "NEW" instead. The card set with the Azumanga cast on the tin with osaka on the backside of the cards have green and white repeating circles with a more zoomed out image of osaka and the words "Azumanga Daioh" on the bottom of the card with the same font as the one used on the tin. The released card has a pure white background with a more zoomed in image of osaka with no "Azumanga Daioh" on the backside but has an orange "あ" logo on the top of osaka. There seems to be no difference between the prototype and released cards with Chiyo and Mr Tadakichi on the backside of the cards.
Websites Game.Watch and Sega.jp have different layouts for the cards. One notable thing is the photo shown on the Game.Watch website show the joker cards, but the Sega.jp website shows only the "Was" card which was under the green faced cards on the right.