I have absolutely no idea whether this is a legitimate cover or not, and I couldn’t find any evidence that it was, but it’s still damn cool. Found it on this blog. I think the article writer’s description is apt: It’s “frumpy” and it “screams ‘Acid rock'”!
Even searching for Penguin versions with an introduction by Margaret Atwood and David Bradshaw and a $7.99 UK (I think that says “UK”) cover price yielded no results. If anyone manages to figure this one out, let me know!