never mind, I found out you can use the built-in called "front facing" on a switch node. But I also found out you can use the same thing on a mix node instead as it's "weight" value. I'm not sure if the switch acts like an if statement, and we all know how shaders hate those, might be best to use the mix node instead ¯ \_(ツ)_/¯
Switch Node
Mix Node