Thanks to everyone for the great info. I actually caught the mechanic installing the O2 sensors on the right side of the vehicle rather than the left, after informing him I had replacements for the left side. I noticed this when he pointed out an oil leak. If he had not called me out to the garage, I would have never known he installed them on the wrong side. Seems that even the mechanics get confused when it comes to O2 sensors! When I questioned him, he said he installed them on his left as he faced the engine.

I found a nice description and picture of Bank 1, Bank 2 for our engines at Location of O2 Oxygen Sensor Bank 1 & Bank 2

Once Again,
Thanks to everyone!