The Borg Engineering Boff was originally an account wide unlock, but it could have turned to a character unlock. Been with the game since launch so don't have a clue about which C-Store items were changed to character unlocks. Doff packs are character only.
I believe the Borg Engineering Borg is both a Account Unlock and a per character C-Shop.
Players that have/had it as account unlock can claim it by legacy unlocks as players that do not have that option (as it was only available as pre-orders for Amazon Collectors/Special Edition or by pre-F2P C-Shop) can get one per character on the C-Store.