True to a point; every card has its ratings, but the "forgetting curve" algo of FSRS is only tuned to the deck (or "option set") that the card is in, not per card.
Each card is tuned to... 2 parameters IIRC? f(Difficulty, Stability, Time) == Retrievability. Time is just time so its not really a parameter, but Difficulty and Stability is solved on a per-card basis.