You can only say that it is beautiful.
I don't think it's from the official team or the Corsican cast, the group is an XT...and other details.
And maybe it's not a prototype either. Furthermore, buying prototypes is a risk, they are basically for storage (I have some prototype parts and they are stored, even on a Campagnolo front derailleur it says: "prototype, non usable").
Possibly it was a special print run for a specific market. For example, 1 month ago I bought a Look frame that does not appear in any catalog, and it was an edition for the North American market and a few units.
Possibly that's it, and that gives it more value.
As for aluminum, as far as I know, the 7005 and 7020 series are the same, basically it is a definition of the country where the pipe comes from. For example, those that came from Taiwan used to be 7005 and those that came from Europe 7020. Oria worked 7020 and being Bianchi and being "exclusive tubes" it is possible to be a custom series from Oria for Bianchi, something like the Gilco Design from Columbus for Colnago.
For the rest, good luck with the sale... I feel like driving to Italy to buy it from you, NTHs are my weakness and I don't have any, Jjjj. I better stop watching the ad before doing something crazy.
P.S. I have kept the numbered saddle waiting for the rest of the bicycle for almost 30 years.