The year of manufacture is shown on a label on the "head tube" of each TW. You "searched"? Really? Half of the conversations on this site are about TW carburetors. Heck! Cut "carburetor rebuild" and paste it into the Advanced Search box above. I got 56 "hits" when I did it.
Then, get a copy of the Service Manual: tw200mainmanual_ocrv2 and follow what it says.
if you run into any other problems, we can help.