How to tell the version of a Galaxy S4 (US/EUR/JAP/HK...) - help needed!

Dear fellow Verge members, I'm about to depart for China and want to buy a Galaxy S4 (I9500 version) there. To prepare myself for the bargaining I have checked the current marketprices and there are pretty extreme differences in price depending on the LTE chip inside those phones (with foreign versions being the cheapest of course). Now my question: By looking at a S4 serial number, how can I tell the market which the phone was intended for? (Like e.g. US, EUR, JAP, HK...) Help is much appreciated!