Hi
The K64 has no MAC address programmed in it anywhere as delivered.
See the following for details of purchasing MAC addresses for your products: http://www.utasker.com/forum/index.php?topic=21.msg67#msg67
It is the responsibility of the manufacturer of the product (yourself) to program unique MAC addresses to each device from the allocated range - a good method is to save these in the PROGRAM ONCE area of the K64's Flash so that it can never be modified.
Regards
Mark
Kinetis for professionals: http://http://www.utasker.com/kinetis.html