Amazon's own page with the screen info (
here) clearly states EInk Pearl, and I have not seen them claim 'improved screens'. In fact, EInk has clearly stated that it will not come out with new screens this year. So yes, the screens are 100% the same. Screens from different batches will always differ in quality, as will newly made ones vs old ones.
And if Amazon really
did somehow have 'improved' screens, wouldn't they be shouting it from the rooftops?