All N9's are RM-696. N950 is RM-680.

Though as you have seen there are different (board?) revision numbers. It would be interesting to know how many revisions exist and moreso what are the actual differences between them.

I've seen N9s with visually different components (mainly screens, but now camera lens too) that share the same revision number, so I'm guessing that "Hardware revision:" only means the revision number of a RM-696 board itself.

Lens is interesting as they advertise it as Carl Zeiss lens so it (presumably) can't be produced by a different subcontractor. Maybe Zeiss supplied another lens with close enough specs somewhere during the N9 production.

Serial numbers might be useful in figuring that out.