The 12 disk ended production 2/1981, switching to the 10 disk 3/1981. If your machine is built in Feb or Mar, there's no way to know for sure until you tear it down. Otherwise, your manufacturing date code should be dispositive.
It's too late to tell you to remove the bucket. Takes a lot of weight off the overhead. Hope you have one or both loader cylinders secured with a spacer designed to keep the loader frame up, the subframe on jack stands and a stack of blocks (or better) under the transmission behind the shuttle. I forgot to tell you to mark the power steering lines. Some guys use wire, some zip ties. You only need to mark 3 of the 4 lines. I put one zip tie on either side of the fitting on one line, two on the next and so on. The first time I used a white pen to mark the lines, the paint came off and I hooked up two of them backwards causing the hoe to steer the opposite direction intended. If you haven't emptied the diesel tank, you might want to do so before you take it out. It heavier than you'd expect. That's all I can think of so you won't have to ask, "why didn't you tell me that before I started."