I received this bag together with a used set. It is bag number 1 and it says copyright from 2007. The content is >10 of round 1x1 bricks and 2x2 round dome bricks, in dark bluish gray and light bluish gray each.
These are very useful parts, but I wonder whether it is better not to open it when it comes from a valuable set.
However, I don't know why the bag says "2007".