The FG42 is a cut weapon that was going to appear in Medal of Honor, Medal of Honor: Allied Assault: Spearhead and Medal of Honor: Airborne.
The map of Fort Schmerzen in the briefing for the mission Attack Impenetrable Fort Schmerzen states that the machine gun towers are FG42 towers. There are no FG42 guns but instead being MG42 machine guns.
The FG42 is a cut-out weapon. The model of this weapon can be spawn using console commands. The player can pick it up, but its model will be invisible. The shooting sounds will be from the M1 Garand and M1903/ A5 Springfield, and the reload animation will be from the BAR. The player will have access to a sniper scope, and the weapon will be located in the place of the rifle. If the player already has a rifle, then raising the FG42 will give him 5 rifle round. Perhaps the FG42 was planned as a German sniper rifle, before taking on the Gewehr 43.
The weapon was cut from the early stages of development.
In one of Airborne's wallpapers a couple of Fallschirmjagers can be seen equipped with FG42s. It is likely that the FG42 planned to be in the game as a weapon of choice for the Fallschirmjager troops instead of the StG-44, but the weapon was cut or never planned to be in the game.