There seems to be a major oversight here - The PanzerFaust-3 is not a disposable launcher.
It has a disposable tube containing the warhead, and a seperate firing/sight unit.
The "launcher" should be the sight unit with no tube, and the "rocket" should be the tube and warhead. The sight unit should be resusable.
For the sake of displaying models and limiting carrying ability correctly, it may be possible to have the tube as the "launcher" and the sight unit as an attachable sight, though you would have to script it to prevent firing without the sight attached, preferable blocking the abity to get out the weapon without a sight unit.
"Pzf 3 consists of two basic parts- a round of ammunition, pre-loaded into disposable launching tube / barrel, and reusable fire control and sighting unit. Before use, the loaded round is attached to the sight / fire control unit, aimed and fired. After discharge,empty barrel is removed from fire control unit and discarded, and a new round can be loaded and fired." - http://world.guns.ru/grenade/de/panzerfaust-3-e.html