No. The Roland RPU-3 Pedal Unit is not compatible with either the FP-30 or the FP-30X.
The pedal jacks on both instruments are designed for connecting the Roland DP series pedals (such as the DP-10 or DP-2) and the dedicated KPD-70 pedal unit. The RPU-3 uses three separate outputs, which are not supported by the single pedal input used on these models.