Sorry if this is asked up thread, I didn't see it when I initially scanned after finding this thread.

I know that you can not buy a Z or P fare and upgrade using GPU from J to F internationally on UA. But reading here I don't see the fare requirements preventing the Z or P upgrading using the RPU/GPU. Am I missing something or assuming there is ON open, will I be able to upgrade to F on the Ghetto 3 class 777 that is still flying that route. I'm feeling nostalgic and would rather experience the old F vs the 2 cabin F (even on the new HI bird) if I'm able and about to buy the tickets and confirm my flight for next week.

Thanks.