NP 205.....missing parts??? Yoke issues

[shanes66charger]

Hey guys, Im putting in new output seals on my 1978 f-150 with the NP-205. I bought a new yoke for the rear as it was worn. After I pressed the new seal in, I went to put the new Rear yoke on and realized that all there was is the nut???? After looking at the front yoke and online, It seems there should be a washer AND possibly a rubber seal/washer (not sure what to call it) that fits over the splines on the shaft to seal it?? Anyone know exactly what is supposed to be there? And, where I could get said rubber washer/seal.........not worried about metal washer, I can get one of those. thanks guys, wanna get this back in the truck tomorrow!!