Have mesh light display original shading?

Is there any way to have a mesh light’s geometry display its original shading with an override? Neither disabling the light nor setting intensity to 0 works.

I am not sure if I understand you correctly, but you could remove your object form the vrayLightMeshProperties and you would get the original shading of your object.

This also removes the lighting from the mesh light. Is there any way to have the light cast from the mesh, display the original shading on the mesh?

You could make the light mesh object invisible to the camera. Then dublicate the light mesh object and apply to it different material.