Could be composites, and plastics; solid state circuitry for the sensors and electronics. The components need only be strong enough to withstand the acceleration stresses that a missile launch would impose, for an hour.
The rocket motors could be the only metal parts, or if the missile warhead needed to be armour piercing. The (default) fuel tank has to have enough for one hour at full thrust, and in theory, you could fuel that only if you expect combat.
If you assume docking space requirements, one tonne could be twelve missiles plus ten percent, and unless the missiles are reloaded manually, there should be machinery that does that particular chore.
If you do customization, any specific missile or torpedo might not fit all launchers or missile racks: you can enlarge missile weapon system, but only shrink the bay allocated ones (which would presume you would shrink the ammunition, though maybe only the launch mechanisms get shrunk and the ready magazine remains the same size).
3D Comparison
