The 324 button filler was made in around 1935-39. The pen material is ebonite or hard rubber (HR). I quite like its warmer and softer feel in comparison to celluloid. Over the years ebonite starts to oxidise and turn to a chocolate brown, as seen on this pen. While the outlined star on the cap top and the simple pen clip are rather plain in their appearance, I actually appreciate the modesty of this design.
The nib on this pen is different from the typical vintage Montblanc nibs. Instead of bearing the "M" for Montblanc inscription, the 32x series has a warranted nib inscribed with 'a', 'b', or 'c', depending on the size of the pen. Size 'a' is the smallest and is found on the 322, while size 'c' is the largest and found on the 326. My 324 has the 'b' nib as would be expected of this mid-sized #4 pen. It is quite flexible! The 32x was offered in a variety of "marbled" colours.
This pen also has a Stoffhaas imprint on its cap which signifies that it was sold by the Montblanc-exclusive stationer Stoffhaas in the 1920s and 30s. Stoffhaas had boutiques in Germany, Spain, Paris, and London, and sold its own stationery and pens - some made by MB identical to the MB series of the time.
Rösler, J., & Wallrafen, S. (2014). Collectible Stars I: 1908 - 1947.