the sig stat is aftermarket, put on a truck that wasn't bought new w/ the turn sig option, and pretty common on these old rigs, added years later - because that part is non-OEM, the fender lights will be too, but there was 2 accessory options available, the one that used the parking light
RPO987607 and others for flatbed/chassis only trucks that used fender top lights
RPO987647 & RPO987643] you can see in those links the "switch housing" just below the steering wheel that will be there if it had the original signals, with a hole in the side for the lever
and the lights on each side of the grill are the parking lights, which should have the dual element sockets even if it didn't come with the signal setup,
marker lights are the ones on the cab roof
Bill
