is one piece episode 604 filler?

Though the Straw Hat Pirates and Brownbeard (along with the dragon) managed to escape into the laboratory, they left a large gaping hole on the side of it. They soon realize that Shinokuni will be able enter the lab in such conditions, prompting the G-5 marines to frantically seal the hole back up with various wooden and metal planks.

They succeed in sealing the hole up as Shinokuni proceeds to spread throughout the island.