Yes, that is correct. I don't own P3D and have never been able to test the gauge functionality. I believe many users have had success with installation though.
Hopefully, someone will assist you if needed.

Please make a back-up of the panel.cfg and sound.ini files before attempting to install!

I have v1.8 for FSX installed and do not know if any of the other released versions have changes to the panel.cfg and sound.ini files.