It depends on how much fat is untrimmed from the skin. Dark meat does have higher fat content in the fibers than white meat, but not so much as to make a difference calorically for most people. It’s like the different in calories between skim milk and 2% is like 20 calories a cup. I guess those add up over time, but you may find the higher fat item to be more satisfying and keep you fuller feeling for longer too, which negates the minor offset in total calories.