Pens of this kind come from Montblanc's third line, which at the beginning of the 1950s was positioned below the Meisterstück and the second line: better-quality school pens and, at the same time, some of the firm's first plastic models. Their hallmark is the star on the cap top engraved merely in outline, in place of the inlaid white star.
The model number is not on the nib but stamped into the blind cap at the end of the barrel. Depending on size it will usually be a 342, the smaller model, or a 344, the larger. A figure such as “140” read off the nib is almost always a misread “14C”; together with the 585 mark it denotes nothing more than the 14-carat gold nib, not the model.
Three things therefore settle the identification: overall length, the imprint on the blind cap, and the form of clip and cap ring. If the imprint is missing because the blind cap has been replaced or polished away, only the measurements can decide between a 342 and a 344.