i too just bought a GH2 and it had the warranty paper that indicated Latin America. i purchased from a local shop that does not deal in grey market. They confirmed it was not gray market. i made them get Panasonic on the phone.
i spoke with a Panasonic warranty person this morning, and they said that paper has caused a lot of confusion and they have gotten a lot of calls. She said, " because my GH2 was purchased in the US, it has a US warranty. Just keep the receipt. That paper was for if the camera was purchased outside of the US". Her words, not mine. i am taking Panasonic at their word.