I did the dual disk conversion to my 78 CB750K.
After getting a couple parts that looked like they would fit, but didn't, I learned that it's not important what year model as long as it's 69-78(not sure about F models, I have a K). It's only important that you get ALL your parts from the same model and year. Even the parts you're going to use on the new right side brake, get them from the same bike as the left side stuff.
Forks, discs, calipers, caliper arms, swivels, all from the same model bike. Don't worry about finding brake lines, you're going to get new braided stainless lines, anyway, right? Bikebandit.com is where I got my lines and fittings, they have custom lengths to build your own system. You can screw the lines right into the caliper, doing away with the metal line section, or you can replace the hard section with (very cheap) hard line meant for a car. I used the brake line flaring and bending kit that Autozone loans out for free.
There are parts from different models that interchange, but getting measurements and specifics from the typical eBay seller is next to impossible.
To me, it's amazing that Mr. Honda had this bike designed so that the brake parts from the left side can simply be taken apart and reassembled to fit the right side. Try finding that on a new bike!
-Sherm