I don't have a parts breakdown for the 3 pt. for the HT tractors, but if that is called the rockshaft, the 3 pt for the older large frames such as the 1250 don't have it.
What I am interested in is what are the advantages of the design for the newer tractors that are so much better that I would not use something similar to the earlier design on an HT tractor? I need to make a 3 pt. for my 1250, why not just make 2 and put the second one on my HT? I want to add the 3 pt. so I can use the implements I pull on my H14 with the sleeve hitch.