I just yesterday went to my local Bayliner parts department and picked up a part for my Maxum. You can search for the part you need on www.maxumcustomercare.com
to get the part number, and give that to you dealer (should be able to cross reference) or search the web with that number.
Replaced my compass a couple years ago and had to go with a smaller one. I wanted it to set up a little higher and bought a cutting board (almost like starboard) and used that as a spacer to fill the hole and also raise it.