The easiest way I found when I was using audacity was to find a lone snare or kickdrum thump and look at the wave form. If they go the same way, then it's not polarity, if they go opposite directions then you have an issue. Now I've heard it enough I can generally listen for to get an idea of when I should flip a channel to test it.
While rare, it's not unheard of for a pair of mics to be out of polarity to each other. It's happened before here.
Now, if it's not a 180 degree phase issue, then I'd be curious how Steve picked it out (I haven't heard samples of said recording, so maybe it's audible).