Collectors date the MonteRosa to the early 1950s, when it appeared as a plainer piston filler below the Meisterstück range and was widely used as a school pen. The factory designation is 042 for the version with a steel nib and 042 G for the one with a gold nib; the added G thus stands for the gold nib and is the only difference in the designation.
Since the two look almost identical from the outside, what settles the matter when buying is a look at the nib. The gold-nib version is generally rated more highly among collectors. The model name follows Montblanc's usual practice of naming its cheaper ranges after mountain peaks.