The base kit, the M60A1, was first issued in 1970. They also did the M60A2 turret, but mounted it to the same hull to make an inaccurate M60A2. The kit was originally designed to be motorized.
In 1988, Tamiya retooled the turret and included new tracks from their M247 Sgt York kit and some new updated parts to create either the US Army M60A3TTS or the USMC M60A1 RISE/Passive kit.
After Desert Storm, Tamiya added new ERA armor tiles, new road wheels and sprockets and reissued the kit you are asking about. It also still includes parts to make a US Army M60A3TTS as well.
It is a solid kit, but there are plenty of compromises due to the original motorization holes in the lower hull. The original gear box was kept into place with screws and the metal axle for the drive sprocket leaves a big cut in the plastic.
But it is still a decent kit, just not worth a whole lot since it was surpassed by newer, better kits.
Just remember, the base kit is now 50 years old.