Yes, they are different. The AKM auto sear has a curved trip arm with a small sear trip surface, while the AK-47 auto sear has a straight trip arm and a much larger sear trip surface.
Despite the AK-47 auto sear's larger trip surface, the actual engagement area between the hammer and auto sear is the same on both the AKM and the AK-47. This is due to the hammer's auto sear contact surface being the same size on both rifles. In fact, the AK-47 and AKM hammers are practically the same, with the AKM hammer having a small radius where it contacts the hammer retarder as the only notable difference.
All AK-47 auto sears are machined steel, as are most AKM auto sears. Some AKM auto sears are stamped steel.