Formula1.com:
In Japan the two Red Bull drivers ran two different front wings, two different diffusers and the same new rear wing the team introduced at the last round in Singapore. This featured an F-duct directed on to the main plane (red arrow), in a similar way to the one featured on the Renault. A new feature was the beam wing, with a delta shape in the middle.
http://www.formula1.com/news/technical/ ... 9/800.html
Hard to tell but possible difference in the end plate openings.