Walt Cunningham once said they did tend to forget this or that aspect of their trip. Luckily, thanks to the books and, pictures and movies, memories were kept.
This meant someone who's read as much as he could about the missions could know better than the astronauts what happened.

For instance, Borman says they took Earthrise during their third orbit.
I've read in a book (Genesis by Zimmermann) that the terminator on Earth (in the picture) showed at what time precisely the picture was taken. it must have been the 4th orbit (each moon orbit takes 2 hours and during 2 hours, the Earth rotates enough to see a difference as to what country is crossed by the terminator).

There's also another aspect.

Alexei Leonow wrote about his spacewalk in 3 books.
The first was during the soviet union era and he couldn't reveal the problems.
The second was just when the cold war melted; some more was revealed, but just a little.
The third was 40 years after his spacewalk and he said everything BUT he also forgot lots of things AND he made up facts too.