Use one of the following entries with the "summon" code.

agp_inventory.PickupW_AT4_Rocket (4 rocket launcher) 
agp_inventory.PickupW_RPG7_Rocket (for rpg7 rocket launcher) 
agp_inventory.PickupW_M870_shotgun (shotgun) 
agp_inventory.PickupT_M14_Incendiary (new grenade that explodes into flames)