One should probably assume that "1 of 8" refers to the first song on their upcoming album and where it was recorded. The band recorded songs in eight different cities.
The other numbers are latitude and longitude coordinates. Those particular numbers are in Nashville, Tennessee. Nashville is one of the cities where the Foo Fighters recorded their album. The others are Washington D.C., Chicago, Austin, Los Angeles, Seattle, New Orleans, and New York.
One would assume that these are actual posters in these cities (look around DC?).
The band has "big news" for Monday. We assume it will be more details about the album.
But, a comic book store owner in New Orleans may have let the cat out of the bag. He tweeted an image of all of the cities combined. It could be the Foo Fighters' next album cover.
Got stickers at shop today.No note/return addy.FF in the corner.8's hidden in pic. Promo for the new Foo Fighters? pic.twitter.com/pJWXdCuLwn— Captain Sarcastic (@CaptSarcastic) August 4, 2014