You can study the Engine Compartment photos here:

http://www.iccahome.org/

Only a few of the metal straps show up. A pattern I see in those photos is this: If the heater nozzles on the firewall are inboard and near the valve cover (as on A body), some metal straps are shown. If the heater nozzles are outboard near the fender, other special heater hose brackets were used, and no metal straps are shown.