Kraig,
Yep, It's an H3. I have 2 H3's. Those wheel weights are very expensive to buy if you find someone who wants to sell them, but are not as expensive and desireable as the single notch weights. I bought a 120 out of a barn with a set and like a dum bass, I let them go with the tractor when I sold it. I'm not sure about the serial of the CCO, I couldn't find it.
Carey