AIR-SAP1602I-x-K9: The ‘x’ in the model numbers represents the regulatory domain.
You can search for regulatory domain at this link : http://www.cisco.com/c/en/us/products/collateral/wireless/aironet-1300-series/product_data_sheet0900aecd80537b6a.html
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You should reach out to your local Cisco SE for more info. Cost would be the same, but you need to make sure you are buying AP's for the country they will be used in.