What does "done wore out one" refer to in casual Southern US American?

In the highly racist and despicable, although humorous, song "Alabama n-word", apparently from the 1960s in the Southern USA, at 1:30 into the song, the lyrics go like this:

I’m glad this tune came along; we done wore out one n-word song.

(All instances of "n-word" in this question is actually the offensive word itself.)

Is this meant to refer to them having previously only sung/played the same one song about n-words, thus happy that they now came up with a new tune for a new song?

Or does it mean (as I always assumed until today) that they refer to having created so many songs about n-word that they are happy that this new tune came along, them finally gaining some inspiration after the "artistic block"?

Basically, is the "one" used as part of an expression/filler word, or does it refer to literally one (song)?

PS: I can’t tell who made/sung the song; I believe it’s miss-attributed to "Johnny Rebel".