No, these don’t turn into Maximums.
The Amiibo Cards for Saikyo Battle Royal are based on the Duelist ID Cards of the main cast from SEVENS that serve as a recurring plot point through the show’s first year.
As a reminder, these cards are only obtainable as a pre-order bonus. See here for more information.
(Another editor: I am unsure, but I believe only 1 random card was obtained per pre-order?)