1) Made in Finland N900 are most likely pre-release (or the so-called summit versions). These devices are rare if they're genuine. Also if I'm not mistaken, these devices should have a yellow sticker detailing the revision version of the device as soon as you open the back cover.

2) I am unsure with the pre-release or summit versions of the N900. However the retail N900 does not have a screen protector when you unbox them. It only has a black sort of like a matte film protector (that is not stuck on, its more like ionised to the screen).

3) Now you're being a bit vauge. On the back of the N900 (i.e. the back cover) should look like this. If the device is new (as you said), it should look like this. There are no other special decals on the underside of that back cover apart from manufacture dates, recycle symbol and a few other things that aren't really worth mentioning. There's no decals on the back side of the N900 once you remove that battery cover.

4) Original N900 and even brand new N900 should never be offered with non-genuine nokia batteries.

5) There should be barcodes on the box and there's labels indicating what IMEI does the device actually have. If these do not match, then that's an instant giveaway that this device could be a stolen device, or a refurbished device and the original owner or subsequent owner lost the original packaging box that came with the device.

6) The output of uname -a does some somewhat legitimate enough (btw, you misspelt PREEMPT)

In either case I am willing to bet on the fact that this N900 is definitely not brand new. There are already a fair few tell tale signs that does not have genuine stuff neither does it have the usual accessories that were meant to come with the N900 like every other N900 when one usually buys from a normal shop.

Depending on how much you paid for it, I would be willing to wage against the seller misrepresenting the goods as brand new when its:

a) Missing A/V cables, nokia cleaning cloth, `matte' sort of sticker,

b) Non-genuine battery, as well as a non-genuine wired headset. By the way, N900 should also come with a quick start guide, and the USB cable is CA-101. Probably also non-genuine N900 back cover too.

c) Most likely sold more than what it should have been worth as second hand item.

As for clones, I have not seen a N900 clone that would be running maemo linux. By you outputting uname -a should be fairly adequate enough to prove that it is not running some sort of hacked symbian OS that is usually featured on fake N900. Maemo linux is almost like a specialised distribution of linux, for a clone that could run maemo linux would generally mean completely identical hardware or otherwise the manufacturer responsible for cloning N900 would have a hard time resetting up maemo in a specific way to accept with the fake/cloned N900.