While I'm not thinking it's definite, there are a couple of things I think lean towards it being possible.
Firstly, there's plenty of background on the Damocles Gulf which involves the Raven Guard fighting the Tau. I would therefore expect the campaign to be White Scars and Raven Guard both fighting Tau.
The other thing is the two types of Strike Force mentioned in WD aside from the Gladius. They were the Javelin and another, the name I've forgotten. One was based around bikes, the other around Storm Ravens and Assault Marines. It was strange these weren't in the codex, but would fit with these two chapters. A campaign box may be the place to introduce them.
Finally there were rumours of a RG specific Assault Squad and a WS specific Bike Squad. These were most likely rubbish but it's plausible that they were campaign box models.
So, I hope it's true, but not holding my breath.