It would take a large leak to get oil on those components as most contamination is from oil blowing back onto the motor while moving.
More than likely the front main seal could be leaking as it would also throw oil in a circular pattern off of the crankshaft pulley and then get the belts soaked as well.
Check the crankshaft pulley by getting some engine degreaser at an auto parts store. Clean the engine and take a short drive. Check the crankshaft pulley for oil and if it is not that look around for the oil leak source. Cleaning the engine off is the only really definitave way to find the leak.