Last October the fuel tank on my 1995 Sportster was full of sealer crud which resulted in major carb work as well as a thorough cleaning of the fuel tank.
According to the factory trained techs, the Motor Company says not to reseal the tank. Just make sure that it is well-cleaned. Then keep the tank full to prevent rust from forming.
Over the winter and early spring I rode the bike a few times. All rides were over 50 miles. I kept the tank full of gas with stabilzer added.
I just noticed a small amount of surface rust in the filler neck area. Anything to be concerned about?