I would think especially in the case of an Italian gun you could check the price list of say a Beretta ASE and then check an SO5 or SO6 and since they are basically the same gun except for ornamentation you would have SOME idea. Or an old Colt catalog and price a single action then price 'C' engraving for it. Should give you some idea of the markup. A Browning B25 and a Midas grade are priced because of the ornamentation. I have a Grade VI Lightning and the only difference between it and the standard grade is the ornamentation. They are both Citori's and have about the same wood. The engraving is nice but not what I would call great by any means. The B25's usually have the engraving signed as does most of the high grade Berettas I have handled. My ASE was totally plain with only a border.