I have been working on my IH mower recently. My mower is a C-21 or so I thought. I ordered a owner's manual for it as I did not have one and I thought it is a good idea to have one. I have rebuilt the cutter bar and painted it. I have learned a few things in this effort. One, the pitman stick is painted harvester cream (refer to the post below for more on cream paint) that is, all of the stick is painted cream. When I cleaned mine up, it was cream. I had thought the metal parts were painted blue, but this one all cream. So, I am painting it cream. I thought the model number was C-21, but as you can see in the first image, the manual covers two mowers; 2C-F21 amd the 34-F21. IH added the tractor model to the related implements from the early days until the mid 1950's or so. In this case the 2 indicates that it is for a 200 tractor, the C is for the Super C tractor the F means Fast Hitch and the 21 is the model of the mower. The other mower covered 34-F21 means there was a mower model for the 300 & 400 tractors. Again the F means Fast Hitch. So the basic mower was the same and IH used the small point Fast Hitch tongs for the 2C-F21 and the large Fast Hitch tongs for the 300 & 400. There are some other differences, but the main idea is that the same basic mower can be installed on ore than one tractor.
The second image is the back of the manual showing that the manual does cover both mowers. You can see that there differences in the mowers. At the bottom of the image is the publishing date 7-25-55. I am guessing that this must be one of the last manuals for implements that carry tractor model information in the model number as I believe that IH did away with this practice in the 1950's. Looking at this manual is a trip down memory lane for me, Just the way things used to be.