This 144 from the early 1950s is in the beautiful dunkel-seegrün (dark sea green) colour more commonly referred to as "green striated". I find the material just stunning! The celluloid 144s came in grey striated, and also plain black. In one Dutch catalogue, the 14x models in different colours were called by names like 144/4 for solid black, 144/8 for grey and the 144/9 for green BUT all were priced the same. The medium size of the 144 allowed it to be positioned as "for men and women". The "Masterpiece" centre band on my pen cap - instead of "Meisterstück" - and the "Made in Germany" barrel imprint, are indicators that it was made for the non-German export market.
Look at how the green 144 stands out next to the other plain black celluloid 14x pens. These are difficult to find with the colour still vibrant, and I think my pen is a decent example. The green and grey colours were also available in the 142 and 146 models.
My pen has a KEF nib. The K stands for Kugel which essentially means the nib tip is shaped like a ball for easy angles while writing. Its an interesting nib tip design, and not so common, but I have to say its a bit boring to write with as it doesn't have character like the early MB nibs do.
Rösler, J., & Wallrafen, S. (2001). Collectible Stars: Montblanc-Schreibgeräte von 1946 bis 1979.