Deleting faces of objects that aren't visible and lighting

I have a question regarding the optimization of 3D objects and deleting faces that are not ever visible. (I am using probuilder not sure if it matters) Regardless I have around 200k tris in my game currently, and despite using a laptop my game is not suffering too badly from frame drops. In order to optimize I was considering deleting all non-visible faces and I would like to know if doing this would cause any types of lighting issues such as light leaks or any problems in general. I do not want to go through the trouble of deleting faces for around 5 hours if later with lighting implemented I will have issues.