Looks like there is a little confusion to whether this is filler or not.

I'd say it's not since it does advance the plot for Team Rocket. Sure it's not full of stuff and nothing really for Ash and that but it still had Team Rocket getting ready for their next mission which if it's shown then would mean this was in fact not filler since it's related to this episode.

Although I don't care, I liked the episode regardless. Had a little shock with Hihidaruma appearing in it's other form which I don't think was in the opening. I wonder how they will do that for the opening though, if they will at all. I'm hoping that when it gets to Hihidaruma it will appear as it's pure Fire self then it changes into it's other form. Unless the other form was in the opening and I missed it, wont know until next episode I guess.