Are you asking about hardware brackets to mount the servos? The pitch servo is mounted at the bell crank just behind the baggage compartment. That’s the only place I’ve seen a servo mounted. As far as the roll servo, it’s either in the wing at the bell crank or under the seat. On my 3 it’s mounted under the seat
We actually have the TruTrak autopilot customized to work with the G3X. I think it was called the GX Pilot. Has been flawless with both the original G3X and with the upgrade to the G3X Touch.
We rolled our own brackets for both pitch and roll based on how it’s done in other RV’s. Pitch is in the usual spot by the pitch bellcrank, and roll is out in the wing next to the aileron bellcrank. It is very tight in the skinny wing, but works.