Deck and Squared

?
I doubt you would need to cut 0.025" or even 0.012" to get them cleaned up & square, you might need to cut them 0.012" to get 0 deck though - depends what the deck height is when you start.
If it has been heavily decked before and your starting with a low enough deck height for the KBs to sit proud then you can have the piston crowns machined (within reason)