In Fo4 they even have deleted from existence SMGs, viable heavy weapons, throwing melee (which with the crafting could be useful now), chinese or foreign weaponry, burst triggers, explosive launchers beyond Fatmans and ML, "survivalist" weapons, old weaponry and the decency, amongst other things.
Btw, who exactly manufactures the .223/5.56mm pistol? The NCR? If so, the one you can find in Vault 15 from Fo2, it just belongs to the Raiders there, whom stole/purchased it, or it's a sealed-off pre-war model?