Fallout 4 DLC Items in Base Game
With Far Harbor and Nuka World installed, are any items added to the game's loot table from the beginning, or are they only available after traveling to the DLC locations?
Like @SGR said for the majority of the loot that you find in the base game area will not be from the DLC. However, I have seen legendary drops which are from one DLC that will either show up in a different DLC and I believe also in the base game area. For instance, I once found a lever-action rifle in the Nuka DLC before starting Far Harbor.
Hope this helps!