This particular Chevy C30 truck may be an out-of-state vehicle not required to be equipped with an EGR valve system. There is a difference with California legal and Federal legal emission requirements. If in fact your Chevy C30 truck is a federal emissions legal truck it does not need an EGR system.
Check our Chevrolet truck's underhood emissions label for indication of whether this truck is California emissions equipped or Federal (49-State) emission legal. If the underhood emissions label is missing, visit a local Chevy dealership and ask them to match up the truck's VIN number.