This may or may not be the neck from Kurt's Epiphone ET-270.
It has popped up on eBay for a ridiculous price.
The seller has pulled most of the photos (including the ticket/flyer) from nirvanaguide.com and is not including any form of authentic certification so there is no telling if it's the real deal or not. The only evidence that shows it may be Kurt's are the replacement tuners, but this is pretty easy to replicate by anyone with internet access.
I received email from readers saying they've communicated with the eBay seller. The seller does not have any actual back story on the neck. They are selling for somebody else under consignment. If you're going to make an offer I would advise you proceed with caution and healthy skepticism.
One of the comments below brought up a great point. The auction listing states this guitar was used on the recording of Bleach which in actuality was not. This guitar was purchased well after Bleach had been recorded.
According to trusted sources "the real neck is documented and accounted for. Currently in a NW collection". I know this was left as a comment below but additionally I've received email with this information.
Another reader has brought up an excellent observation. Kurt's Epiphone ET270 was outfitted with Gotoh tuners from the late 1980s/early 1990's. The tuners in the photographs of this neck appear to be Schaller tuners found on Mexican made Fender Stratocasters from the early 2000's. This information cannot be verified and the information is intended for entertainment purposes only.
Disclaimer: This guide is not claiming that this neck is a fake, nor is it claiming that it's real. This guide is only reporting opinions based on observations, not facts. This guide is intended for entertainment purposes only and has no business affiliation with collectors, buyers, or sellers. It was never intended to be any source of such information or a "buyer's guide" for Kurt's guitars. The guide's primary intention is to obtain close up photographs of Kurt Cobain's guitars and speculate as to where they may currently be.
More photographs from the auction: