As with any other group of people, lots of people who are Catholic don't even know half of the tenets of Catholicism. At least where I live. I basically slept through CCD, and even in my adult life, I've heard a 'huh?' response when I bring up something as big as Vatican II.

I still think that you're right, but you'd need to do a little more market research to prove it out. Even people who know it wouldn't be 'real' might still think it amusing enough to do it anyway.