Is there a pink bar at the very top of your bootloader which says 'Locked' or 'unlocked'?
If not, then no, your bootloader cannot be unlocked.
However, any device which has that there, should just be able to select 'other supported device' from the list and unlock.
at least, that's as far as i understand it. It certanly worked on mine..but then mine is an EU device.