depends on whether the caliper is fore or aft of the leg
I did wonder if that was the reason but the R80ST and R80G/S were both aft of the leg just like an R65
OK, the Brembo FO8 calipers were "invented' at the behest of Ducati and where fitted to the front of the forks. Hence the "left" or "right" handedness relates to their original fittment.
In our case we have a "right" caliper fitted behind the fork to the left side, and a "left" caliper fitted behind the right hand side fork leg.
This has caused ongoing confusion for as long as FO8s have been around.