Launcher Grenades require a grenade launcher, which is stand alone or underslung. Grenade Launchers are firearms and require that production path.
Missiles and Missile Launchers require a team, building them from scratch is unrealistic.
Note to Players: Information here is considered metagaming. Your character should not reference or use these numbers in game to determine who should roll for specific skills.
Book 2, page 22, "This Skill functions with respect to producing 'simple' explosives such as TNT, nitroglycerine, blasting caps, etc., as Pharmacy Skill does with respect to drugs."
Book 2, page 23, "This Skill is an advanced form of Simple Explosives Skill and operates in the same way but deals with more advanced explosives such as plastic explosives and other such wonders of modern technology."
Book 2, page 21, Under Pharmacy: "Task period is usually 1 day. Once the task if finished a the number of drugs produced is determined." For explosives we break that down to 60 minute blocks rather than days since they don't need to be made in batches.