EHogan,
Welcome to the site...the part your are asking about is called the bonnett. The original bonnetts were made of steel and a lot of them did not make it as they were the most exposed to the elements and just rusted away. There were replacement or repros
made of fiberglass but I expect they would be hard to find. I have 2 600 series series Tokheim, one a 610 and the other a 620b. They differ in that one (610) has a gate valve that was opened and closed to allow the gas to flow from the cylinder and was referred to as a dry hose. The other was known as a wet hose as it allowed the gas go to the nozzle and it was released from there. Hope this helps.
Mick
