In AZ, you probably don't need to worry about painting the tank. You don't get the moisture like other parts of the country and I seriously doubt you'll be taking this car out if you get another freak storm like you have now.
Here in the rust belt, ANY TIME I drop a tank, I coat the hell out of it with paint, especially the seam where all the stuff collects. It works too. My 77 Grand Prix was originally a southern car. But it went through 14 winters here and the paint really helped that tank. My B Body 78 Olds got the same treatment even though it doesn't go out in the rough weather. Ditto for my wagon tank because it does.
Here in the rust belt, ANY TIME I drop a tank, I coat the hell out of it with paint, especially the seam where all the stuff collects. It works too. My 77 Grand Prix was originally a southern car. But it went through 14 winters here and the paint really helped that tank. My B Body 78 Olds got the same treatment even though it doesn't go out in the rough weather. Ditto for my wagon tank because it does.