I just noticed what looks like an alignment gauge for the rear arms. Can anyone confirm what this gauge actually shows and why would the left side be so off center compared to my right one?

Right gauge on center


Left gauge

 

The marks aren’t an actual measurement of your alignment, they are there just to give a rough starting point and then each mark can be used to reference how far it’s been adjusted. Remember, the vehicle is an assembly of a bunch of different welded and stamped parts, with various manufacturing tolerances for each part. When a large piece is stamped and welded, the final result might be plus or minus 1/32 of an inch (or half a millimeter, if you will) because that’s the very nature of stamping and welding steel. So the factory makes all the parts, bolts them together, with the marks aligned then the vehicle goes to the alignment machine which measures the initial alignment and then tells the worker “right rear add 1 mm” for example so the worker looks at the marks and then moves the setting accordingly (perhaps each mark is half a millimeter, so the worker moves that adjuster two marks.) Bottom line, don’t sweat it.

 

Thanks for the thorough explanation!