I think it would be easy to recognize them, as they probably won't even have android on them to begin with, like those fake iphones that come with that weird operating system which has nothing to do with IOS.
This can be a tricky one, however the fakes I have seen in the past generally have fairly obvious differences including either not having the branding or at least not having it spelt correctly. if in doubt, contact your local Sony Xperia support team:
