I quite agree, thanks for your response. Provenance would be crucial. As an outside observer I would suggest that if people like yourself, who are fortunate enough to handle so many original daggers, have only ever heard rumours but never actually seen one, then I would never take the risk. It seems to me that this model was a one off piece for the Reichsmarshall, and was not reproduced as an industrial dagger during the period.
If it had a quality damascus blade that complied with all known standards of III Reich period production, then that would be harder to judge. But the etched blade looks as though it could have been reproduced quite easily post war.