Still sounds to me like "I won't sing that roack and roll" and I won't lay down my old guitar".

Either way, that's what it presumably means - ironically if it's "I want to" and literally if it's "I won't". And it sounds the same either way, because of the way the spoken or sung language works

That seems to me such a neat bit of ambiguity in a song that I'd like to think it'ss intentional. I've been trying to think of other examples where this kind of thing happens in a song, but I haven't yet - intentional use of mondegreens.