Tim, Good reverse logic there. Where might this "tag on the chassis " be located ? My doubts on the correct man / carb. arise from two observations. First is that the fuel line from the pump is flared at the carb attach end. Yet I don't see a nut on the line anywhere. Strange ! The carb inlet fitting has a bead. There is no provision for a fuel filter. Second is the red ( high temp ) RTV squeeze out at the manifold parting surfaces. Also the electric choke feed wire appears to be home made. I have also been questioning the thermal vacuum switch on the water line off the thermostat housing for smog test / inspection requirments. There is absolutely no installed wiring or hoses for it.
Brings up a question of being original. If no one knows what was original then how does one call the installation original ?