The accessory switch screws #9427312 originally had a copper washer. I've verified this with a Leeds-build 1970 Skylark as well as a Flint-built 1972 Skylark. I'm not sure if the current AMD screws are this way.
I have taken apart many 70-71 frim Flint and Framingham and never saw copper? I think it is overkill.
