Currently the New Genesis bundle's WOK uniform boxes can only be opened by Federation captains.
However, it is possible for Klingon-faction captains to have qualifying BOFFs (Marauding reward renegade BOFF, Kobali BOFF, etc.) who could wear the uniforms, so why can they not be unpacked and used for such BOFFs?
And in fact, it's possible for ANY captain to have a BOFF of ANY faction and gender (for costume purposes)... via various means (Romulan BOFFs from the Fleet Embassy, Jem'Hadar BOFFs from the Gamma expansion pack, etc.) so... every costume box should have faction locks removed.