The only thing I will have for the 66 RCV will be a schematic not a tech manual. This fork is really simple to rebuild so I'll give you a blow by blow here.
Since this is a pumping rod fork, all you have to do is remove the top caps. This will expose the spring or springs, remove.
Now drain the fork by flipping it over. Pump it a few times.
With the for flipped over you can remove the footnuts from the bottom with a 15mm socket.
With these removed you can remove the lower casting.
If you wanted to change the seals a special tool is needed for installation. So be careful here. You will need to remove the dust seal, then a clip, then the main oil seal.
Once the seals have been reinstalled via a seal press tool, install the clip into the groove.
Take the dust seals and slide them onto the stanchion tubes. This will help you reinstall the stanchions into the lower casting and seals without damaging the main oil seal. Grease the oil seal and dust wiper prior to installation of the stanchions
With the stanchions installed into the lower casting, you can now attach the footnuts. You will need a long rod or use the spring to push the pumping rod thread up through the base of the casting. Attach each footnut and tighten to 15Nm (pretty f'n tight)
With the foot nuts attached you can now add oil, 7.5wt fully synthetic oil.
Pour oil into both sides of the fork. Fill it to about 3" from the top to start with. Now cycle the fork up and down to let the oil fill the lower assembly. Once this is done, let the fork sit for a few minutes to let the air seperate and float to the top. Now set the oil hieght.
Set the oil hieght to 55mm from the top with the fork fully compressed. This is a good hieght but if you are a lighter rider you can go down in hieght to 60-65mm. This will give the fork a more linear spring rate once built up but it will bottom-out easier than the 55mm hieght. With the oil hieght set just extend it and add the springs and top caps.