Yes, precisely because it is a 500 mile race and driver weight is an infintesimal factor over the course of the entire race. I would think experience would weigh much much heavier.
You didn't answer the question.
Question: Just imagine for a minute, two cars, identical in horse power and weight, traveling straight ahead for 15 miles. The only difference being one driver weighs 100 pounds less than the other driver. Who would you bet on winning the race? Would you consider this a fair race?