Fallout 76: 6 Important Trailer Clues You Totally Missed
3. 1776-2076 Poster
The bedroom shown in the trailer has a poster of everyone's favorite Vault Boy in a stars-and-stripes hat. Underneath him is a banner with the dates 1776-2076.
People who know their history may have heard of a small thing called the Declaration of Independence - a document famously signed in 1776. It's understandable the vault dwellers would celebrate the 300 year anniversary of this event - people in the Fallout universe are very patriotic.
But it's also worth remembering that according to the lore, most vaults were only occupied when the bombs started falling - October 2077. It's a bit strange that there'd be a poster celebrating an anniversary a year before anyone would be living in it.
Perhaps, then, the dwellers of Vault 76 actually inhabited and locked the vault before the bombs fell - it would make sense, since the poster celebrates independence. The vault itself seems to lack all of the experiments and misery of most vaults. Immediately following the poster is another clue which helps put this in context.