The company's internal record system on which the laser-etched identification numbers are based was not introduced until 1990. For older pens even the manufacturer cannot assign a date; an enquiry to Montblanc about a pen built before 1990 will come to nothing. The number is therefore of use for dating later examples only.
Further pointers come from the imprints: the addition of “West Germany” places a pen before reunification, while “Germany” on its own suggests later manufacture. Details of the specification help as well, for instance that later 146s carry the engraving “Meisterstück No. 146” on the cap ring and are fitted with a two-tone nib, whereas older examples have a nib in plain gold. The ink window may take the form of a continuous ring or of narrow transparent stripes.
Even so, a firm identification is not always possible. During transitional phases different variants ran alongside one another, and a pen that has been in for repair at some point may carry components from another production period, a clip fitted later for example. Comparisons of size remain reliable nonetheless: the 146 is distinctly larger than the 144, and the 149 in turn more substantial than the 146.