How to tell RAK 2287 concentrator regions

We have many different RAK 2287 concentrators for different regions. The label on the RAK2287 module does not have the region name on the label. The only unique information on the RAK2287 modules is the serial number.
May I ask how to identify the different concentrators?

Check the bottom of the module. There are two spaces for resistors, one labeled 915MHz, one labeled 868MHz.
Only one is assembled and does indicate which frequency range the module is build for.