Every time the narrator (William Conrad) mentions the Civil War, he is angrily interrupted by a Confederate soldier, in full battle dress, loudly correcting him: “War Between the States!”
Sometimes the scene switches to where the soldier is, and sometimes he barges into the scene being narrated.
At one point, some sort of time travel mechanism is deployed, resulting in the outcome of the war being reversed.
As the narrator explains this, the soldier interrupts him again when he utters the words “Civil War”, demanding that he call it War Between the States.
The narrator says something like, “Quiet! This time, the South wins!”
The soldier replies, “Oh. OK. Then it’s Civil War”.
The above quotes are from long-ago memory. I saw part of it as a kid, and didn’t understand the satire.
I looked and found that this testy revisionist Civil War soldier appears in eipisode 5 of the story arc Wossamotta U, but I found the episode on youtube and the above exchange doesn’t take place in it.
I remember pretty much every episode of Rocky & Bullwinkle, but I don’t recall this at all.
If time travel was involved, you may be thinking of an episode of Mr Peabody and Sherman, but this doesn’t ring a bell either.
There was a Bullwinkle’s Corner where he recited a parody of the poem about Barbara Pritchey (“Shoot if you must this old grey head/But spare my union suit, she said!”). Boris Badenov was a Confederate soldier in this one, but I don’t remember him saying the lines you mention.
I just got done watching that episode. Here’s what happens:
Wassamatta U plays a team of ringers in a football game. Bullwinkle mistakenly uses an old Civil War battle plan as a playbook, and through some tortured plot, WU re-fights the last two years of the war.