I'm thinking about buying a used Flagship heritage. I found this one, but i'm not sure, especially, about the caseback, because it's inscriptions are different from the pattern on longines site.

Another yellow is that the seller doesn't have the papers of the watch. But, since I'm from Brazil, that's not a definitive red flag, because of our importation taxes, it's normal to people travel and come back with a watch without papers, case etc.

that said, can someone help to identify if it's a fake or not?