Second man on left has a rifle grenade launcher on his M1rifle. Maybe the light but sure looks like the finish is worn off from use. Pouch for launcher on his right hip. Possible ammo bag for rifle grenades on his left side.
I enjoy looking at pics of WWII US front line infantry to see how each man choose to wear his gear and gear type. ie Pistol belt vs cartridge belt. Leggings vs loose pant legs vs late war two buckle boots. Belt with or without suspenders (battle harness) etc.
Bet the order was just given : "Move forward to contact."
For a guy my age these men were our fathers & uncles and dads of our school friends.