Well, ok, but that's assuming that Marty is Sour Cream's father - and that it was this trip that conceived Sour Cream. It seems easier to assume the episode is set 80's-ish based on the clothing and music. BUT. There's also no reason to think the Gems pay enough attention to human culture to remain fashionable, or…

I’ve been enjoying the conversations here for a long time, but never thought I had anything to add until today.