is one piece episode 252 filler?

At the Sea Train station, several marines and agents are gathering around and Robin is seen within the group as well. Corgi tells Robin that CP9 will be coming shortly and tells Robin to get onto the Sea Train.

He orders two guards to take her onto the Sea Train. Close by and hidden, Sanji is seen and wonders what he should do.

He notices that Robin could easily take down the guards but believes she is planning something. Suddenly, CP9 make their appearance with Rob Lucci leading the group and Blueno is carrying Franky and Usopp who the two keep yelling to let them go.