From the petcock (if there is one) to the carbs/injectors must be fire sleeved. If you've got an in-tank fuel pump -- no fire-sleeve at all is required.
That said, fire sleeve is yet another bit of inexpensive insurance.
As for plastic lines -- some plastic line ARE fuel-okay, and they might be installed downwards from the end of the required firesleeve. That's what that rule implies. But if the fuel-rated plastic lines are before the valve -- fire-sleeve is required.
Back to statement (above): Fire Sleeve is inexpensive insurance. It's your private parts that are sitting within a foot or so of the fuel line. Toasted testes, anyone?