Yes, they would. As the pad linings wear, fluid is displaced from the brake fluid. If you're the type that compresses the pistons back into the caliper with breaking open the bleeder, then you may want to hold off on adding brake fluid. If you top off the fluid level in the reservoir and then compress the pistons back in without opening the bleeder, you'll have a big mess when the brake fluid pushes out of the reservoir as you compress the piston. If you do crack open the bleeder, then go ahead and top it off.