I take it neither of you actually read the article?
Astronomers have discovered rocky planets orbiting stars, and they're orbiting stars in the "right" zone - the zone that would allow for liquid water to exist.
There have been four such discoveries, and the scientists are predicting that if their equations are accurate, eight more should be discovered in the next several years, bring it to a total of eight. After that, it just becomes a process of statistical probability to predict how many exist in the galaxy in total.
Until they land on one, or see it looking Strangely Earthlike - with life and stuff - through a telescope, it’s just a rocky planet orbiting its sun, not an “Alien Earth.”
My impression is that they didn't. The Kepler mission is all about actual observations. Kepler will give us data about where to point even better telescopes in the future.
Like I said guessing.