There were two executions of the Autavia Reference 2446C, the first execution having a black dial with applied steel markers, and the second adding red accents and black inserts in the markers and hands. Silver / white test dials were made for a third version, which never went into production.
Three Register (Ref 2446C)
Autavia — Reference 2446C, Mark 1
Autavia, Reference 2446C -- Mark 1 has earlier case (smaller teeth on bezel); black dial with white registers; polished steel hands with luminous inserts; white chronograph second hand
Autavia — Reference 2446C, Mark 2
Autavia, Reference 2446C -- Mark 2 has second case (larger teeth on bezel); black dial with white registers, and red accents; markers have black inserts; polished steel hands with luminous and black inserts; red chronograph second hand