There is always a place for an anode rod.....they go in the drain hole.
But as noted Atwood doesn't require one even though aftermarket has them for sell.
Anode rod is a sacrificial rod of magnesium (Suburban OEM Rod) or aluminum (Suburban Optional Rod). Suburban requires them because of STEEL Tank that is glass-lined.
Atwood doesn't require them because of Aluminum Tank clad with zinc alloy