Amendment 12:
The Electors shall meet in their respective states, and vote by ballot for President and Vice-President, one of whom, at least, shall not be an inhabitant of the same state with themselves;
Electors vote for say “John McCain of Arizona and Sarah Palin of Alaska.” I am fairly certain the state of residence must appear.
It doesn’t seem reasonable that Puerto Rico could get both halves of the ticket more easily than a U.S. state could.