Ironically, it's only today that I have removed the disc from my 400, also to have the new rim and spokes fitted. To the best of my knowledge it's the 1st time that the disc has been removed, and I've owned it since 1989, (it's a 1976 model). There were no tab washers under the fixing nuts as they are flange nuts. The tab washers you have pictured would be OK for ordinary plain nuts, but would not do their job properly on flange nuts. If my memory serves me correctly, the last time I saw these was on a CB750 rear sprocket. Just use the flange nuts, making sure that the mating surfaces are nice and clean and use a torque wrench for the required tightness. If ever we get back on the road, looks like it could be a good year for shiny wheels!!! Regards, Mick.