Over drive question on a 2000 Chevy S-10 pickup?

My question is on a 2000 Chevy S-10 pickup is does it have an overdrive in it on the transmission? It has a 2.2 L 4 cyc engine in it with an automatic transimisson. It has the letter D 3 2 1 on the gear shift gage. The letter D does not have a circle around it like most of them do if it does have over drive on it. But is the letter D for overdrive and the number 3 for regular drive for city use?