Answered: Rule <R7>c regarding legal washers.

Greetings,
Rule <R7>c allows: “Any commercially available #4, #6, #8, M2, M2.5, M3 or M4 screw up to 2” long, and any commercially available nut and/or washer to fit these screws."

I was wondering if commercially available washers could include the type of washer shown here: https://www.mcmaster.com/#90127a009/=1a0e331

Thanks.

Yes, these would be legal.