The Trijicon RM01 RMR Type 2 LED 3.25 MOA Red Dot Sight will not fit your P320 as your P320 uses a Deltapoint Pro optic cut, not an RMR cut. You would be able to fit optics like the Leupold DeltaPoint Pro, Eotech EFLX, Sig Sauer Romeo 1 Pro, Sig Sauer Romeo Zero Pro, and Sig Sauer Romeo 2.
It will fit Sigs with the Pro cut slide such as the VTac, X Series LE Pro but require a plate due to a slight gap.