Nokia has like 20000000 models, it's not like it's the first time they'd end a production run to make something else at the same factory. As to the source, it seems to me like his contacts are closer to the production sites than Nokia management. That could mean he'll get fingers on prototypes without knowing what they really intend to do with them, or that he'd be able to get info on things like how many screens ordered, etc.

Also, I don't mind being in a niche except that I know niches get left behind all the time.