The President is told that the Haitian army has "two Bradleys with 120 millimeter cannons". The Bradley infantry fighting vehicle is equipped with a 25mm auto-cannon; the 120mm gun is on the much larger Abrams main battle tank.
It is possible, though unlikely, she is referring to the variant of the Bradley equipped with the 120mm mortar.
Sam's full name is Samuel Norman Seaborn. The large letter of the monogram on his shirt shows a large N in the middle, with two small S letters on the side. The large letter is traditionally the last name, and should be an S.