In the Guadalcanal episode, Basilone's forearms were heavily burned by the machine gun barrel. In this episode, when he undresses with Lena, his forearms are unscarred.
Under the Iwo Jima attack, Bassilones squad moves through the trenches and encounters a machine gun nest fortified under an airplane wreck. When the bazooka guy of the squad fires on the MG nest, the dummy rocket in the bazooka stays there after the bazooka has been fired.
After the wedding, Lena is in front of the church and is wearing open-toed sandals. In reality, women didn't wear those kind of shoes with formal wear back then (and actual photos show she wore closed toe footwear).
While in the squad bay, the Marines were informed they were shipping out. Destination unknown until they are at sea. When the Lt. departed, the Marines celebrated the fact they were going to see some action. Two Marines can be seen shaking hands formally, and then they do a soul shake clasping of hands. That hand shake evolved after the 40's.