Larry,
Check our thread " Believing is hearing".
I´m sorry to insist, but for credible results it´s gotta be a blind -*test*-('"), with perfectly calibrated output levells, meaning you must engage someone to do the cable swaping for you.
If you know in advance which is which, you´ll be driving yourself unintentionally into a falacy / trap. That is unavoidable, no matter how golden-eared you may be.
Anyway, if you do carry out the left - right comparison as you intend to, make sure to engage the "Mono" button in your amp, if it´s got one. Many stereo recordings have quite different contents on each channel, and that won´t help in your proposed method.
Please keep us posted on your findings. Oh, and above all, have a great time. I wish I could be there to do the cable swaping for you.