I looked into it and they did release a x2 version that was unlockable...
personally I would never buy a chip that had disabled cores for the simple fact that if one part of the production when bad whast to say something else wont fail later on?
It seems like there is a greater chance of that happening one one that has already been deemed not worth to be an x4, or even an x3 chip.
Granted at times they do just have a quota to meet on production so they will lock the cores and ship them as an x2 or an x3.
Mate I hope you the best on getting one of the ones with all "good condition" cores and have a happy unlocking