At least blanking out the last two digits of the year protects the author from the Mr Pedantics of this world. You know the ones -
"You state that your story is set in 1885, yet on page 237, you mention the new moon rising on April 12th, whereas the most cursory study of the almanac will confirm that the new moon in April of that year didn't occur until the 15th of that month..."
This. Modern equivalents are TV voice overs along the line of, "The events you are about to see are real. The names have been changed to protect the innocent." Uh huh.Or ... I don't know ... since the stories that do this seem to be mostly or all written in the first person, to give the sense that the narrator is being discreet about the actual year when those shocking occurrences (therein related) took place, so as to avoid tainting innocent individuals with the suspicion that they might have taken part. And by the narrator pretending to veil the truth in this way, the idea might arise in the minds of readers that the story might in fact be true in its essentials.
It seems to me that more than just one letter was probably purloined....D—. Why I've no idea. It was a very dull story too (The Purloined Letter)
It first appeared in the literary annual The Gift for 1845 (1844) and soon was reprinted in numerous journals and newspapers.