answered
2017-10-21 10:27:19 +0200
Unfortunately, you can't ensure that with a 100%. You can check the exact model number that you order, e.g. for the black model, 1302-8005 and 1302-9401 are the standard, unlockable ones. However, this does not mean that other models can't be unlocked a well. Also, we experienced some vendors (yes, I'm talking to you, Amazon) sending you other model numbers (refurbished operator ones which can't be unlocked), but in this case you can at least return them by simply refer to the wrong model number.
You can always ask the seller of the device if he can check the bootloader unlock status (e.g. if you order from ebay and co), but bigger retailers probably can't answer you that question. So pay close attention to the model number you order and / or clearly state that you want a device where you can unlock the bootloader, this may make returns easier if you get a "wrong" model.