Yes. Bay and brown are caused by the agouti gene on a black gene. Agouti restricts the black to specific areas. "A" agouti is bay, which restricts black to the legs, tail, mane, muzzle, and ears. "At" is brown, which restricts black very similarly, but lightens certain areas: muzzle, around the eyes, flank, elbow. "Soft areas" that will not be faded by the sun.
Browns are also far easier to identify during the winter because their coat changes dramatically from summer to winter.