A star with unnaturally pointed corners is a clear counterfeit feature; equally typical are visible furrows between the three cap rings. Despite a serial number and higher weight, it is therefore a counterfeit. Detailed comparison overviews of typical counterfeit features can be found on fountainpen.de, e.g. in the PDF comparison of rollerball counterfeits. Anyone buying a Montblanc at strikingly low prices or from disreputable providers should reckon with counterfeits.