Nah that's still entirely clientsided and infact I've seen people break shaders so that their game is bright even in pitch darkness, which means it'd be a pointless exercise even if it were possible.
Other than that you can replace brick textures to remove the bright glow on brick outlines when shaders are off, I believe clients see the updated textures
In other news: changes to LMG have been made - barrel changing should be more intuitive. Tapping reload once will always attempt to reload ammo, double tapping reload will attempt a barrel change. If one of these operations cannot be completed it will default to the other. Barrel changes also have a timer similar to the reload one