yes, if done correctly, BBT can help verify whether you are actually ovulating. if there is a sustained rise in temps so that there is a biphasic pattern (low first part of cycle, high second part), it means you have ovulated. if it just up and down the whole cycle, then either ovulation is not occurring or the temps could be inaccurate due to changing sleep patterns or not having it in your mouth long enough before taking it, etc.
also temps have to be up at least by .2 degrees than the first part of the cycle. also they hv to be up for atleast 3 days after oculation