It’s dress, but the tab on his shoulder says “Honor Guard” so maybe he’s detailed to the 3rd Infantry “Old Guard”? Somebody here probably knows. I see parachute & air assault badges, plus an 82nd Airborne Patch on his right breast pocket. Also aviators wings.
He’s an Old Guard guy, he is wearing a buff strap on his left shoulder. I know when I was there that was only awarded to Old Guard soldiers upon successful completion of “new man training”. TOG has the usual support positions you find in any other Infantry Battalion along with others not normally found. The Fife and Drum Corps is one example.