No. Water heater manufacturers use two different types of tanks, one aluminum and the other a glass-lined steel tank. With the steel tank, an anode rod is installed into the tank (with pipe threads), and the anode rod will sacrifice itself, that is, decompose until
the aluminum or magnesium has completely gone from the base. An aluminum tank does not require the use of an anode rod. Dometic/Atwood water tank are aluminum. Also, the plastic plug is a safety feature in the event of overheating.