crooked swing arm from factory?

I found out the hard way when i made my custom swing-arm. I assumed the stock one was symmetrical, so i made my custom arm symmetrical. When i put the wheel in the new arm the sprockets didn't align. I measured the stock one and low and behold, slightly offset. It took a different set of spacers, and I had to cut out and refit one of the braces to work.

yes the swing arm in question is on a kz550A.
i’m not sure if i’ll attempt anything that precise. probably try to measure without removing the swing arm first.
but thank you for excellent illustrations and clarification!