I believe that diesel also reacts with metallic zinc, so OEM fuel tanks are unlikely to be galvanised.

I have had a problem with WVO in a home made fuel tank made of galvanised iron. The fuel filter blocked repeatedly with a grey, "sago pudding" consistency substance. It was explained that the oil, a weak organic acid was reacting with the metallic zinc, forming a salt of the Zinc and triglycerides.

I drained the tank, washed with petrol and then acid washed the tank to remove the zinc. Hey presto, no more problems.

Regards,
Tony