KZ440 Serial number question

I have a 1981 KZ440, at least that how the previous owner registered it, It was manufactured 8th month of 1980 So to me it could be either a 1980 or 1981. Anyways there are so many variations so I would like to know how to find out for sure the model year and if it is a A1, A2, B1, B2, D1, Etc. Some parts I need are slightly different for each model and I want to order the right part the first time if possible. Serial number is JKAKZHC12BAxxxxxx I just xxx'd out the last 6 numbers as they are likely not relevant. Any help is greatly appreciated and hopefully your help will get this thing going for me in time for summer.

Try this website for information about your bike:
www.motoverse.com/tools/vin/kawasaki.asp

It says it is a 1981 KZ440-C which I have never seen listed anywhere for parts. Anyone know which other version of this bike may be similar or the same?