I can't figure how those bars would ever get bent. They are mounted on an even plane and rotate on the same plane. Even sitting, there isn't any weight or force that should cause them to bend. My car sat for over 30 years and the bars haven't bent.
That said, I bought a "set" from a member on here a few years ago and one was bent. Checking the numbers, they were both for the same side. I can only guess that the one that was bent had been installed on the wrong side and that caused the bend.
The ONLY difference is the way they are PRE loaded... we would
wind up the bars to get a pre known set to them.... they all
started out the same... the hexes were all the same.. when you
pre load them they in up with a set... that would dictate which
bar went on what side of the car... thats all there was to it..
and I seen them have them have a slight bend in them new... it
didnt matter at all
EDIT
The reason for the pre load was for warranty.. without
the preload the cars would settle lower after a short
period of time... so we started pre loading all the bars
