First of all, I believe that the expression that you're looking for is - In Memorium. The word memorandum refers to a brief note that a person jots down on a piece of paper. From the word memorandum, we get the word memo.
As for Heston, he was a homophobic, anti-semitic, misogynist racist much admired by none other than Daivd Duke. Heston trivialized the Holocaust. A case could be made for Heston's acting skills, but as a person, he was hateful and vile. And this fact made him the ideal spokesman for the paranoid organizational collective known as the N.R.A. - a group that is even more dangerous to American society than all of the religious cults combined.
American society is much better off now that the words, in memorium, can be put before Heston's name. But I decidedly do not hope that Heston is in Hell. In fact, I hope that he is in heaven, with other luminous exemplars of American society such as Roy Cohn and Joseph McCarthy. Moreover, after he approaches the throne of God, I hope that Heston is greeted by a Jewish, Negro, lesbian.