Collectors compare the piece with the documented Bohème Platinum Doué pictures on fountainpen.de; a brown crocodile barrel is not a regular Bohème Doué variant but a counterfeit, since this barrel was never officially offered. Black stripes on the Montblanc ring are present on the genuine Bohème and not a counterfeit indicator, contrary to initial assumption. Auction ident numbers like IY1073508 Germany alone offer no authenticity guarantee, since counterfeits frequently mark such numbers. With a misrepresentation in the auction text (also implicitly through category choice), the legal warranty claims to rescission and the right to challenge for mistake exist; even subsequent deadlines despite the exclusion clause of private sellers are enforceable in such cases.