Other than color (usually indicated with an extension), they have the same part numbers - so I'd say they can be used interchangeably. Check at Harper's online parts fiche like I did...
For example, the Norge listing shows:
05100230F2 Fuel tank, grey (from the 2010-2013 listing)
05100230F2 Fuel tank, grey (from the 2000-2009 listing)
Interestingly, the list for the earlier bike also shows
05100235F2 Fuel tank, grey - which is about $300 more expensive!
Unfortunately, I have no idea why there would be two different grey (Excalibur Grey, also known as silver to those in the real world) tanks listed, nor why the price would be so different. It's also possible that the 235F2 listing has been superseded by the one shared with the later bikes.
