is one piece episode 258 filler?

Sogeking introduces himself to Sanji and Franky and his theme song plays. Sogeking continues singing his theme song but Sanji and Franky aren't fooled by Usopp's disguise.

Franky wonders why Usopp is dressed up like that and Sanji says that Usopp has too much pride to show his face to the rest of the crew but still wants to help save Robin. Franky tells Sogeking to come over and Sogeking does.

Sanji then begins a meeting for a plan to save Robin. Sanji says that they must find out which train car Robin is in while Sogeking asks if they want to know where he's from.