Bidyanus1,
Yes you can swage .458" bullets up to .470", and you can also draw .474" bullets down to .470".
However in your case you would need to be certain that the chamber neck of both barrels will accept such a large increase in diameter.

Seating a .470" bullet in place of a .458" bullet, will increase the cartridge neck diameter by .012".

While the groove diameter of your barrels may be oversize by that amount, the chamber neck/s may not.
The cartridge/s might not chamber at all, or far worse might chamber with the cartridge necks jammed tight in the chamber/s, causing a big increase in pressures.

I suggest you measure the chamber neck diameters of both barrels before even thinking about using .470" bullets in your double.

Please keep us up to date on what you find.