No drilling required. The MV-P Adapter Plate allows you to mount a SteelMaster™️ to a guitar that is equipped with a Master MV-P Vibrato. You simply attach the adapter plate using the two top wood screws on the MV-P Vibrato then install the SteelMaster™️ to the adapter plate. 

You have a Mastery Bridge but you are not sure if you need the MV-P plate?  If your vibrato is shaped like the one in the picture of the blue guitar above, you will need one. If your Mastery Bridge is shaped like a standard JM vibrato and dropped into the standard JM vibrato mounting holes, you do not need it. 

SteelMaster™️ sold separately.