I've noticed that musicians are a light-hearted bunch. Good thing. So I suggest we stick to that and laugh when one of these musical or other blops comes along.

In Ken Burns' Civil War documentary, there is frequent repetition of Ashoken Farewell. It does seem to fit but it was created by Jay Ungar in 1982, over a hundred years after the war.

If an anachronism really bothers you, I suggest you put some words to the offending tune, words that make sense in the situation or just loosely making sense, which I did for Ashoken Farewell.

Some will wonder how to do that. There's always a dozen YouTubes about any task, but what I do is start by writing some prose that sez what I want to say, then work it over to make it fit rhythm and rhyme.