EDIT: my bad with with the late- vs mid-2009. I meant the mid-2009
The first unibody was up-to the mid 2009 and is not as good. weak battery, the screen is not good. BTW, it was not labeled with MacBook Pro - it's just a Unibody MacBook.
the 2.53 is not the first, but high-end 13" from the second revision ;). I have the 2.26 from the same revision and it's great.