If that's correct, aren't there possible risks for flying a plane that had such a long period of inactivity?
This is the really big problem Boeing now faces.
For these planes to fly again they need to be certified safe to fly again.
However since the FAA was one of the last authorities to ground the plane, it really does not matter what outcome they achieve in their current investigation.
Other aviation authorities around the world will take their own time to investigate if the plane should be allowed to fly.
The conundrum for Boeing is it wants the plane back in the air ASAP but I'm sure many of the world aviation authorities are in no real rush.