How can two presumably older Montblanc cartridge fountain pens without further model designation be assigned to a concrete model based on the nib image, cap and serial number?

The first pen with completely golden nib and flat ends can presumably be assigned to the Generation range or a model range around the mid/end of the 1970s; it is rather an entry-level model with correspondingly low collector value. The second writing instrument with two-tone gold nib and inscription "Meisterstück" belongs to the Classique range, presumably a 144 (recognisable by the plug-on cap). Today usually only on the 149 is the model number engraved on the cap ring; older examples often bear no visible model statement. Via the serial number engraved under the clip (e.g. CG235...), the production date can be enquired about with Montblanc customer service, which helps with narrowing down the model.