First Appearance of the Little Red-Haired Girl?

Since the new Peanuts Movie has been announced and released, I've read several articles and reviews claiming that the new movie was the first time you ever see the Little Red-Haired Girl. Reading those statements, I knew something was wrong because I remembered seeing her before in a TV special. Thinking back, it was this TV special she appeared in. She shows up at the New Years Eve party after Charlie Brown invited her. Unfortunately for him though, Charlie Brown fell asleep on the porch reading War and Peace and missed her visit.

Now, knowing that she did appear in this special, is this the only special she appeared in, or was she in others as well? Was this special the TRUE first appearance of the Little Red-Haired Girl?