Not very official imho. On the one hand her appearance in the polish Playboy has nothing to do with the russian callender. That's because a human made of flesh and bone is not the same as a render model (surprise! *g*).
And for the callender, well, they definitely looked for a modell that resembles the computer model of Triss and I think they did a good job. But she's only "official" for the callendar, not for a potential future movie. She's a modell, not an actress.
I'm not saying it wont happen, but I think it's a long shot, infering from a callendar on a movie...