The plot thickens lol while i sleep. 6 speed & all. They were quite a torquee old thing so only needed 5 in those days but 6 is nice & close ratio.
Hope i don't regret saying about steel last in. You're not beating it up like a motorcross bike.
I really enjoyed my R5 with its piston port inlet growl that everything had back then until 1972 when those damn flappy inlet things arrived & squawking like a duck haha.

I'll have to look online and compare what I have to the RD clutch. 

Arrows mean it'll only fit with those aligning so in theory you must have a splined pressure plate. So sounds like you're on a winner all the way with likely an RD hub with the backing for the fiber.

I edited the arrow comment. I was saying that I know the later RD's had arrows on the pressure plate. Mine does not have the arrows.

Oh, that's a shame but never mind. She's working.

I ended up with a steel fitting against the pressure plate, it fit and then readjusted the clutch. I used one from my existing plates. Now the clutch is stacked correctly for the early style inner hub and pressure plate. I did delete the rubber cushion rings. The clutch feels great now.