I am posting this to attract the attention of wolfe10 whose posts indicate he really knows this topic. All others are invited to reply, as well.
My used 2003 Southwind came with an Atwood GC10A-3E water heater, which worked OK. Being of a cautious nature, I decided that I ought to replace the anode rod, not realiz..ing at that time that Atwoods did not require and could be damaged by one. When I pulled out the drain petcock, there it was, an almost eaten away anode rod of unknown age. Apparently, one of the two previpous owners had installed it at some time unknown to me. Anyway, my question is, could this have sufficiently damaged the tank that it should be replaced? Assume that the rod's fitting was steel.