Ah...here we go...
Hey...
Is there an echo in here?

Ok ...Answer : NO. Not unless you find something like a seller on an ebay auction who offers "squaredeal" and that may be as good as it gets concerning any kind of guarantee.
Any business selling brand new n900's are going to be from Asia ..and they are all kinds of wrong. I wouldn't touch 'em.
Parts ...some ...maybe. But it is possible to find brand new parts and assemble your own. Much more expensive than buying a little-used well cared for used one. There is a member floating around here who just recently built one...it was pricey.

Also I really really really really really really really really really REALLY think you don't need to repeat the same questioning post 3 times to get one answer.

The BEST suggestion if you want better than some unknown strangers "guarantee" .. I would suggest buying from a fellow member here at the Buy and Sell section. No one will lie or steer you wrong knowingly, no one would risk their good name amoungst their peers, also who is going to take care of a device properly? But a fellow member.