Both models are documented in collector literature: the Montblanc 254, similarly to the 252, was made between 1954 and 1959 in various versions; the Montblanc 24 was produced parallel to the 22 between 1960 and 1970. For further research the search functions of collector forums like penexchange.de are recommended, even if there search terms like "Montblanc 24" are partly ignored due to too-frequent occurrence. Collectors' meet-ups, e.g. get-togethers in the Pforzheim region, offer additional possibilities for knowledge exchange.