Correct, but notice, as we were kinda getting at, the Roxas, Axel, and Xion symbols aren't included on this art piece, and did not show up in-game.
As for the ones that *are* included, here's what we have:
On the Light set, from left to right: Sora, Riku, Kairi, Mickey, Terra, Aqua, Ventus
On the Dark set, likewise: Master Xehanort, Ansem, Xemnas, Xigbar, Saix, Yong Xehanort, Marluxia, Vanitas, Larxene, Demyx*, Vexen*, Luxord, Riku Replica*
*Note: These three asterisked I am not totally certain of, but seem within reason and the best possible guesses; the rest of them I am pretty much certain of, and can dig up reasoning and evidence to support them if need be