goodroi - 1:41 pm on Jan 30, 2013 (gmt 0)
I haven't noticed this before because I tend to pick one version (www. or non-www.) and stick with it. The other version is redirected so it should never appear in the serps.
I am not sure why you would want to verify both versions, at a quick glance that seems it could introduce possible dup issues. I haven't had a lot of sleep the last few days so maybe I am overlooking something.