It is possible to not take this feat at weapon master level 1 if that class level is taken at an epic character level. (An epic bonus feat may be substituted for weapon of choice.) However, not taking this feat will render the other weapon master feats impotent (until this feat is taken, for which there is no second opportunity until weapon master level 13). Thus, this is generally a bad idea unless the single weapon master level is being taken for the bonus feat.