Rotor Thickness

I know this has been discussed before but I can not locate the information I need. Hopefully some one will be able to help. My MKIII manual states that rotor thickness should be between .250"-.260". Mine shows .262" at the very edge and .255" in the center. The center has the chrome worn down to what might be the layer of nickel but not down to the cast. My question is what is the thickness of a new cast rotor without the chrome plating?
I am curious to know if they took a standard rotor and plated it with the end result @ .260".

Pete