There are two variants as mentioned in the documentation. To be more precise, it could be worth mentioning that :
ST B-L475E-IOT01A1: 915 MHZ (US LoRa)
ST B-L475E-IOT01A2 : 868 MHZ (Europe LoRa)
This can be important for one intending to use board with LoRa instead of or in addition to Wifi and purchasing the right one from day one.