Go watch the trailers.
You can figure this out on your own if you do.
Oblivion and Skyrim are in vastly different locations and timeframe. Fallout 3 and Fallout 4 are in the same world with the same companies. In this same world, there are things like Sugar Bombs with advertisemant posters that are the same in DC and Boston
They probably aren't reusing most of Fallout 3. Meshes for examples, are improved for lots of things in the traler and many things look completely different from Fallout 3. For some things that have no reason to be changed like the Sugar Bomb poster, they just used the same one made from Fallout 3, hence why we see the exact same one in the trailers.