there is some fat there, or else his belly button would be a hole, as opposed to a straight line.
how long has it been since you haven't lost any weight?
i would throw fasted morning cardio sessions (as simple as walking) keeping your heart rate below 120-130. work up to an hour on off days.
if your weight still won't budge, slowly cut your carbs back and increase your protein a bit.
these suggestions are assuming your diet is spot on.
why on earth you would want to lose fat at this stage of your physique, i have no idea. good luck.