All CONMEBOL Libertadores player items are Rare and will count as Rare whenever Rare players are asked for in a Squad Building Challenge. Even if a player's base item was Bronze, Silver or Gold Common, the corresponding CONMEBOL Libertadores item will be Rare. All CONMEBOL Sudamericana player items are Common.
Conmebol Libertadores cards do not count as rares in the main game but does so in the webapp/companion ap.