In close-up, the Deadly Valentine note shows that the words have all been directly printed onto the card, instead of being glued-on from newspaper clippings, like serial killers used to do back when. A few of the words have a pink background, others blue. Newspapers don't have such page coloring. However, this printing simulation might not have been visible in its original airtime, in 1970s televisions.
About 1 min 20 secs in, the woman wearing a green suit is heard saying: "You know Pete? I still can't get used to the idea that I need a body guard". There's just 2 problems with that: 1) It's not her voice, she has been dubbed by a voice-over. 2) The actress' lips aren't moving.