Why ask for method and duration?
Results depend on salt concentration, temperature, exposure time and acceptance criteria.
Does passing guarantee marine durability?
No. Real marine use can include wet/dry cycles, abrasion and galvanic contact.
What should be checked after exposure?
Appearance, resistance, plating integrity and any relevant shielding requirement.
Project note: Use supplier data as a starting point. Validate the finished assembly at the relevant frequencies and environmental conditions.