It is presumably the Montblanc 1266, a Meisterstück piston filler with sterling-silver thread guilloche, which was made between 1971 and 1976 in small numbers. It has a rhodium-plated 18-carat gold nib. Early examples had a massive feed with a metal-mounted ventilation hole, later ones a flatter, more reliable feed. Due to the rarity, the collector value in flawless condition lies up to 1000 euros. In the standard work Collectible Stars, this model is not listed.