It would be far too costly for the car manufacturers to provide different levels of rust protection for different markets. To suit bulk production volumes, equipment on the production line to apply paint and corrosion protection can only handle one process which must be common for all markets. Only if a model is built in more than one plant, could there conceivably be a difference.
In the case of equipment which is installed in the vehicle on the assembly line there can be differences but these are usually to cater for specific legal requirements or customer preferences in the respective markets.
Sometimes, but very rarely because of the high cost involved, equipment is added by the importer at the port of entry. This would only be for something which is considered vital for a particular market but which the manufacturing plant is unable to provide. For relatively low volumes, it may be uneconomic to do so in the plant itself.