On GTV Phase 2a Lusso there are 2 different MVS codes for 3.0 V6 24V with gearbox type specified in it:
163.943.0.0 – GTV 3.0 V6 24V 5M LUSSO
163.963.0.0 – GTV 3.0 V6 24V 6M LUSSO
But Medio has only one MVS: 163.953.0.0 – GTV 3.0 V6 24V MEDIO, so by deduction it should be available with lesser options by default: 5M. But it was in fact available with 6-speed manual gearbox C530.6 as we can see on the example below.