Yes.
Golds are the most rare, Silvers are the second rarest, and Base cards are the least rare. All Base cards are unlocked through gameplay for free and are the easiest to obtain. All Silver cards are awarded to skilled players via Ranked Rewards (i.e. ranking highly on the leaderboard) or Conquest mode. All Gold cards are awarded via Conquest to the exceptionally skilled players. Every week, eight unique cards will be available as Golds to be won in Conquest. Every week, there will be a new set of eight cards that can be won.