I'd rather say there is quite some tolerance in installations; know this was noticed from time to time on solid axle Opels when they put wider rims on, our Volvo 240 is also off a bit to the right I noticed.
I just remembered something.
The camber is adjustable on the rear axle.
The camber way off spec will produce the results as mentioned above.
The FSM does have a rear axle alignment procedure which would should put the axle on dead center.