Well, I would highly suggest you check the bolt pattern of the Z32 vs RB series. I think if you hold the flywheels up to each other, the holes don't line up. I believe both are 6 bolt, but have different spacing.
OTHERWISE, if they were the same, then Fidanza would have the same part number for the RB and VG flywheels but they don't.
However the clutch surface (240mm) is the same.