I think I'd wait for YouTube to delete the video, especially since this song is in the public domain.
I posted a slide show of Christmas photos for the women's center where i do volunteer work. The person who made the slide show video, had used a excerpt from Beethoven's 6th Symphony. The composition was in the public domain, of course; but Google identified the piece as a recording from a certain symphony orchestra. Google said there might be ads shown before the video is displayed, but they didn't tell me to take the video down. I guess the ads were supposed to pay royalties for the symphony recording.
-Joe-