RD400 clutch lock washer or belleville/conical washer?

[NYSingh]

Putting in new clutch plates, and I noticed that the washer under the main clutch nut looks to be the belleville/spring washer that is normally used under the primary gear nut on the crank (part # 214-16119-00-00), rather than the lockwasher with the tab (part # 90215-18131-00). I was going to order the correct tab lockwasher, but then I noticed that this build video https://youtu.be/LcK1bNo8wiU?si=ye0dUt7WqVRFO3q9&t=1200 (20 min mark) seems to use the same belleville/spring washer and not the lockwasher.

Question: is it ok to use the belleville/spring washer under the main clutch nut, or should I order the correct tab lockwasher per the parts catalog?

[1976RD400C]

I've seen either one used. The RD I bought in 1976 had the bendable type, but others had the belleville. Never seen a problem with either one coming loose.

[SoCal250]

My '79 had the tabbed lock washer 90215-18131-00 under the clutch nut when I took it apart last summer. It had been worked on before so who knows if it was original or not.

The parts book for the RD400F lists the belleville washer 214-16119-00-00 behind the clutch nut and the tabbed washer on the primary gear. (opposite of your 400C parts drawings)