yes and no
omnidirectional = round microphone
so unless those BOSE headphones have a round microphone then they do not have a omnidirectional. I took a look at the Bose Headset and it looks like a standard unidirectional microphone.
Gaming headsets usually have an omnidirectional microphone
Apple uses a unidirectional microphone (flat and one sided) . But it will pick up omnidirectional sound. This is probably the reason BOSE ( and apple) call it an omnidirectional microphone