Same here.. you can’t buy the servos or the autopilot control buttons yet but you can pre wire everything so it’s ready to plug-in and install when they get the certified check done. We Had our panel cut for the autopilot control so it will be a easy install
There are a couple of 177s that did on this thread
https://www.pilotsofamerica.com/community/threads/panel-upgrade-with-dynon-hdx-and-avidyne-540-just-waiting-for-the-ap-certificatation.127509/
Dave at Ramona Avionics did the CAD drawing and has the DER that has the engendered endorsement for the structural changes. Give him a shout and he’ll be able to help.