I'm pretty sure that is a variation. The clothing is different than the one on the box, and at the bottom of the flyer it talks about the variation. They probably did it to boost nami sales..it looks like you can't tell if you get the variation just by looking at the box. Whenever I went to any of the stores that carried those feeling figures, there were always cases filled with namis!
Sorry for the long wait, here's the picture of Sanji's box:
They don't have an online store, but I think there should be some stores selling that figure individually online.
I took this picture on a whim, so I thought I should include it. Trading seal foils:
I'm missing the ace one and the luffy one, I've got two more that aren't shown. I think Sanji looks funny there, he's not normally that wide eyed or innocent looking.