We haven't seen Len pick up the decks but in episode "A Rider's Resolve," we seen Len has five Advent Decks. Six Riders have been vented, Len wasn't there when Torque was vented, so it makes sense he doesn't have that deck. The decks he has are Incisor, Camo, Thrust, Sting, and Spear. He vented Incisor, so it makes sense he has that deck. Torque vented Camo but I remember seeing the Camo deck left alone. Strike vented Thrust in front of Len, Kit, and Chris, so it makes sense that Len could have grabbed it. Strike vented Sting instead of Len, so it makes sense Len would grab that deck. And Kit vented Spear, so he must have given the deck to Len.