Actually its not true they are all the same, they all have the same model number but they don't all have the same modem. Case in point I flashed my wind phone with Bell's file through odin and my modem no longer works. And as I can't roll back ( I flashed lollipop ) I have to wait until wind ( if they ever do ) release a lollipop update with the updated modem firmware. I know it should be all the same but I'm telling you it simply IS NOT TRUE.
I've even tried restoring my old modem files through TWRP, as I had a full backup of everything and still no go, it shows that its connected to a tower but it doesn't register on any network. My IMEI is correct, and non listed.