A reliable judgement is only possible based on sharp photos; a textual description is mostly not enough for the experts. A smaller size and a slight imbalance need not be an authenticity problem, since Montblanc has built differently dimensioned models. Striking spelling errors in the engraving (like "Meistersück" instead of "Meisterstück"), however, would be a clear counterfeit feature and should be precisely checked. A check at a Montblanc specialist retailer is usually free of charge and quickly possible.