Anyone know the minimum thickness the front rotors may be turned to on a 2007 f150 supercrew 4x4?

2007 truck , almost new .rotor should be good for another cutting. then i took my new truck,maybe 2 years old, to dealer they tried to tell me i needed to replace rotor on my 4wheel drive. i took it somewhere else and got probably another60 k miles on orig. rotors.

1.180 inches is new. 1.120 inches is throw away. Thanks