Yes there is a difference there. Most non-child rape pornography is fantasy, most child pornography is actually documented child abuse. However, I believe that no information should be outlawed and that includes real rape pornography as well as child pornography. The dangers of legalization of possession of these forms of pornography are vastly exaggerated, the actual evidence shows that criminalization of possession of these forms of pornography is more damaging to society than their legalization would be, and indeed that the criminalization of these sorts of pornography is counterproductive to the stated goals of those who are in favor of their criminalization.