Montblanc never made the Bohème in this form. Where a piece is described as a one-off, a personalisation or hand-workshop work and at the same time shows a roughened or scratched engraving panel together with a missing cap star, it is not a factory version but a production model reworked after the fact by its owner or by a third party. The white star belongs on every Bohème and is never left off at the factory; Montblanc executes engravings cleanly and by machine, not as a coarsely worked-over surface.
Interventions of this kind add nothing to the value, they are damage. They reduce the collector value substantially and are to all intents and purposes irreversible, since the affected parts could only be replaced outright. Advertising copy in a sales listing is no substitute for provenance: what counts is whether the piece matches the documented production specification. In case of doubt, only Montblanc itself can give a binding opinion on authenticity and factory specification.