When the rocket explodes via grenades and horseshoes, weapons of light has no affect. However, when it explodes by other means, weapons of light will increase damage. That being said, all rockets without grenades and horseshoes will be affected by the bubble. Furthermore, If you want a grenades and horseshoes rocket to do bonus damage, you have to hit a rocket or other solid object within range of your target. The rocket will explode on the obstacle and deal damage to your target. Since the rocket didn't explode by means of grenades and horseshoes, it will be affected by weapons of light. That all being said, the explosion will most likely be such a distance from the target that weapons of light will not compensate for the lost damage due to being far away.