Ok.. I'm almost sure the body is wheel thrown, and it was thrown on an asian wheel.
In asia the wheels always spin clockwise, where western wheels spin counter clockwise. When you throw clay and pull while it's spinning, it will make that spiral. The radial strokes you also see, is from cleaning up the trimming bits. When you work on the lid hole, bits are shaved off and fall into the pot. That's true on both hand and wheel thrown pots. The radial lines are scrape marks from a steel tool used to scrape them off the bottom and get them out of the pot.

The lid is a bit confusing, but I think I have an answer. There are several ways to make a lid. When I throw a lid, I throw the whole thing upside down, and then trim the top. But this one I think is assembled. I think the potter threw a thin cylinder and then cut that off for the skirt, and then attached it to the lid. Also, the lid was thrown as a shallow bowl, and then the two were attached. The knob was added after while it was spinning. That undercut on the lid is exactly what I get when I hold a bamboo skewer at the base of the knob while it's spinning. If the knob was also hand built, it has a different shape where it connects to the lid. It's either sharp like a ball just stuck to the lid, or has a sort of molded look with a flared base that looks... like a chess pawn.

The thing that I'm not sure everyone understands is that you can not make a teapot on a pottery wheel. All you can do is make parts that have radial symetry, and then assemble the pieces. It's not entirely different than how you would do it with just hand tools. It makes the body easier, and a bit in the lid, but otherwise, there's just as many "gluing" steps on a wheel, as there are on slab built teapot, and spouts and handles are exactly the same.

Anyway, I'm almost positive that it was built from some parts that were made on a pottery wheel.

BTW, I don't think that wheel thrown means not yixing.
It just means it was wheel thrown.
Yixing is just an area. It would be unrealistic to think everyone in the area of yixing built pots the same way. I am also unconvinced that a hand built pot is really any better than a wheel thrown pot. It's just harder and more time consuming to make it from slabs. I think if you asked any group of potters that were making round things if they would do it on a wheel or from hand built, they'd pick the wheel. The only reason I can see to build by hand is a matter of economics since hand building is much cheaper and the required tools are alot more accessible.

@michelf - 

Hi Michel, nice seeing you here!

When you say "made on a stick" do you mean having the clay rolled around a stick and then shaped for the curve after take it out?

@michelf - 

Thanks, that's what I suspected too -- I actually think this pot could be Japanese in origin. It looks suspiciously like Bankoyaki clay, instead of Yixing. The texture is not right. Reminds me of those Chaozhou pots, but with a dark brown colour instead of the usual red. Maybe it can be achieved through some sort of firing technique... I don't know.