I am sure those are just urban myths. Not every word is an acronym you know.
Some jerk once told me that fuck stood for "fornication under the consent of the king" and I was like "Nooooo I don't think so."
Only one I can think of which actually is (as far as I know) would be good ol' port out starboard home, unless what ever musical that delightful song that's from made that one up too, in which case, no, words in common usage tend to be actual words derived from other languages.