Pilot screw o ring?

I was going to remove my carbs one last time for a cleaning as its getting warm out, I was reading a lot about the being o rings under the idle mixture screws on post 1980 models, I want to replace them, I removed the screws and there was just a spring, no o rings or anything else? Here is a pic

motorcycle carburetor parts-pwk fuel mixture screw — NIBBIRACING

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Pilot screw o ring?

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