I also visited Scopes, a break from my usual boycott of that dishonest lying left-wing website. I remain skeptical and these urban legends always manage to accrete all of the supposed corroborating details cited in this case as time goes on.
My very first impression was that it was staged and that someone was reading from a script. Pure acting, especially the laugh. That was not a spontaneous and unrehearsed recording as one hears in the typical voicemail.
I avoid Scopes. But, this clip was so old few places to research.
Of course , this is U.S.A. you are always entitled to your opinion.