It is a Montblanc 1124, made between 1976 and 1980. The value of such models can only be roughly estimated and depends strongly on condition and nib width; corresponding comparison offers can be found in relevant collector forums. Important is the historical context: only from 1991 has Montblanc positioned itself as a luxury-goods manufacturer; before that the product range reached from the cheap school pen to the Meisterstück.