Alrighty... Lights Off now works great when non-3d objects are selected. However, Lights On doesn't work right. I still have to individually select just the 3D layer(s) that use lights.
Here's the code I'm using based on your input:
function LightsOn(){
var myLayers = app.project.activeItem.selectedLayers;
for (var i = 0; i < myLayers.length; i++){
if (myLayers[i] instanceof AVLayer && myLayers[i].threeDLayer)
myLayers[i].acceptsLights.setValue(true);
}
}
function lightsOff(){
var myLayers = app.project.activeItem.selectedLayers;
for (var i = 0; i < myLayers.length; i++){
if (myLayers[i] instanceof AVLayer && myLayers[i].threeDLayer)
myLayers[i].acceptsLights.setValue(false);
}
}