Absolutely could be worth zero. There are a few Bechstein adicts afficianados who will always pay a little more than market value just because it is a Bechstein, just as there are folks who pay thousands for those old Vienesse style Bosendorfers with the leather covered hammers.
Thanks -- that's about what I thought. BTW I didn't fail to realize that in a way it couldn't exactly be worth "zero" because somewhere there's gotta be somebody to whom a piano like that is going to be worth "something" as long as it plays half decently, which this one does. But when you take into account that a given seller might not find such a buyer for quite some time, we could be talking almost zero.
P.S. Thanks for not taking any offense at my post. I was afraid it might seem like I was challenging you or something (and if I'd been near the computer I would have edited it). I was just trying to clarify, and it looks like you got it.
My main point here -- and I should have been clearer about it, so let me do it now: IMO it's really important to get a piano like that checked out by an independent technician.