Where 250.146,[A] references "a rivet or thread locking or screw locking means", would this include those little 6/32 nuts with the machined serrations or the serrated lock washers attached to them?

I've always just connected a pigtail to the device, but would be good to know the details.
Other than looking up the individual manufactures listing, is there any identifiable marking on these covers that would indicate they are listed for grounding?