Oddly, the parts book for the 2020 does not show an opening for a switch of any kind in that location. Also, I can not find any keyed switch in the parts listings in the parts manual.
It is too difficult to dig through the electrical schematics. However, from long experience with 5 Airstreams, I know that the schematics are not accurate, with the exception of what they might be using on the factory floor.
I think this one deserves a call to the factory. Please post whatever you find. My curiosity is killing me.
John W. Irwin
2018 Interstate GT, "Sabre-Dog V"