Crush ring gasket?

[Jungerishere]

I just picked up diff kit that includes fill and drain plugs with crush ring gaskets. I noticed that the new fill and drain plugs have rubber gaskets built-in (see second photo of the plugs with green rubber gaskets). Since these have the rubber gaskets, do I still need to use the metal crush rings?

[Ricky Bobby]

I don't believe so, just wet the gasket with oil before install

[Jungerishere]

That's what I thought. Thanks RB.