is one piece episode 958 filler?

At the new Marine Headquarters, Fleet Admiral Sakazuki discusses the Seven Warlords' dissolution with Fujitora. Although Sakazuki expresses disagreement with the choice, he decides he cannot change the decision.

When discussing Kaidou's situation in Wano Country, they end up mentioning a certain Rocks. The other Marine officers hold a meeting and the name Rocks also comes up.

Sengoku decides to tell the story of the Rocks Pirates. The Rocks Pirates were a group of extremely violent pirates who even fought each other onboard the ship.