Here is the list of country codes used by Apple devices.
MB123XX/A or MC123XX/A is the device code and XX is the regional identifier (or however it is called). This code you can find in this list:
AB Egypt, Saudi Arabia, United Arab Emirates B Ireland, UK, also used for some replacement phones C Canada CZ Czech Republic DN Austria, Germany, Netherlands E Mexico EE Estonia FB France, Luxembourg FD Austria, Liechtenstein, Switzerland GR Greece HN India IP Italy J Japan KN Norway KS Finland, Sweden LA Colombia, Ecuador, El Salvador, Guatemala, Honduras, Peru LE Argentina LL USA LZ Chile, Paraguay, Uruguay MG Hungary NF Belgium, France, Luxembourg PL Poland PO Portugal PP Philippines RO Romania RS Russia SL Slovakia SO South Africa T Italy TA Taiwan TU Turkey X Australia, New Zealand Y Spain ZA Singapore ZP Hong Kong, Macau