I am not sure this is relevant, someone at the Dark Reverser's site has said that his(or her) kindle has been always 3.0, but seems like utilizing a defferent DRM scheme after 9/3.
Maybe something has happened OTA without changing firmware level number?
Secretly deleting /test directory perhaps?
It don't do anything unless you've got a /test directory on your unit. And ecostin does have it, and you, like 99.9% of other users, probably don't.