Provide the data to insurance, let them fight about it. It's their problem now. This should never have been something a vehicle owner needs to worry about if they have insurance.
Ridiculous. I guess nobody has the time to verify that these containers have in them what they say they do? Or do the shipping companies know it's a vehicle but don't bother checking VINs or anything? Maybe it needs to be the liability of the railways and shipping companies that what they're transporting is legal, otherwise they have the incentive to keep plausible deniability and get paid.