More 1.15 pesos rates to the United States.
3: These 5 centavos are from the "Cara Fea" or "Ugly Face" printing, which is not nearly as common as the other printings.
4: 1.15 pesos; Although this cover has two partial postmarks middle bottom, these are not from missing stamps. The rate is correct, and there is no clean surface left behind by a fallen stamp. I believe these partial postmarks were created when the postal clrek postmarked multiple covers at once all overlapping slightly.
