Fulvia C. was No.447, with A.Doria being No.452.
Cristoforo Colombo, being the sister to Andrea Doria, used the same casting but was marketed in a box with the ship named and identified as "Art.462".
On the underside of the casting itself, the identity A.Doria is blanked out, but the No.452 is still visible.
Regarding Michelangelo, both Sammelhafen and Galerie-Maritime registers have it as number 446, but as Jeff says, it does not carry a number on the casting; it does have both names (Michelangelo and Raffaello) cast. Interestingly, Mercury also included the shipping company name amongst the underside casting marks...I don't recall seeing this with any other manufacturer. One other casting mark on all except Michelangelo is "G.Patrone"; Michelangelo has "Modelcraft" instead. Anybody know if this might have been the actual casting foundry?
Finally , I have 3 of the range in display style boxes; each model is mounted on a cardboard scenic base/background and enclosed by a clear plastic lid.