The Montblanc 1266 is one of the four-digit models of the 1970s and is comparatively hard to come by today. Its nib is a regular source of confusion: it looks pale and silvery and is therefore often taken for a steel nib, or for a replacement fitted later.
In fact the 1266 left the factory with an 18-carat gold nib that is rhodium-plated, that is, covered with a pale layer of rhodium. A silvery-looking nib on this model is thus the correct original state and no defect. The thing to check when identifying such a pen is the stamping on the nib, which states the gold alloy — a pale nib with no alloy marking would argue against its being the original.