1- what venue is he selling them in? if it is trustworthy sale venue that you know...(ie like ebay) I would imagine he's the real deal. Not to mention ..if a scammer or thug wanted someone's money nowadays...he'd be trying to sell you a genuine "ipone" He'd hardly be trying to ensare with a couple n8x0 devices. Rest at ease there.
2- good price...If you had the money one of each is my suggestion...esp if it comes with batt . and all the gear.
4- Most importantly ....you must not look at it as simply a gadget...or another internet tablet..or some kind of phone alternative...it is really a full computer...hell you can run a few distros on it..The stuff you can do is pretty cool. It is only limiting by your curiosity and intention.
To poorly coin the phrase and quote... the NIT (Nokia Internet Tablet)..."...Is the beautiful mistake the Gods made ...that man got his hands onto..."