All iPhones are assembled in China, however certain models destined for sale in certain countries or regions may have limitations to comply with local laws.
Check the model number in Settings->General->About->Model
If it has a "J" before the "/" It was intended for sale in Japan and the camera shutter sound cannot be turned off.
Apple does not sell "apple certified and refurbished" phones on Amazon. This is something done by some reseller that is supported by Amazon, not Apple. Amazon is not an Authorized Reseller. If you look at the Model Number in Settings>General>About, and Google it, it can help you understand where the device was designed to be used. There are no phones "Made in Japan". If you have used the Mute switch on the side of the phone and you can still hear the camera shutter, then it is very probable that it was made for one of the areas, like Japan, that do not allow the shutter sound to be muted.
How do I know if my phone was made in Japan?
