First off. When you say you "NEVER" had the oil light come on before you started it, this is not good. The oil light needs to come on when the ignition is turned on and before the motor is started. If it does not, how do you know you have oil pressure (or not)? I'd figure this out first.
Wet sumping happens when either the oil tank drains down into the engine case while the engine is sitting. Or when the oil pump is pumping more oil into the engine it can remove, which will fill the crankcase with oil (not good) and drain the oil tank. On the last year of that version of the XB motor, Harley introduced a revised oil pump with a much larger "scavenge side" than previous years to help out with this. In 2008, the oil pump system was completed redesigned and is unique to the 2008-2010 motors.