Anything lower or close to 4.5mm should be replaced. Those EBC rotors are $420 for a set of 2 for the front. You have to buy the EBC pads to go with them in order for the EBC Warranty to be valid. This is the EBC rear http://www.murphskits.com/product_info.php?cPath=130_157&products_id=433
I would ask the tech what he means by 'lock up'. Pads low, rotor worn out, leaking brake cylinder?
Is 67,000 early for a non aggressive rider?
When Murph refers to this as a set, is that a set of front, or a set of front and one rear?A set consists of the two fronts.
http://www.murphskits.com/product_info.php?cPath=142_146&products_id=411