355 Bypass valve gasket gone - Suggestions?

I finally got around to attempting to eliminate the bypass valve rattle by turning the unit to lengthen the stem. Like most, the paper thin gasket that the valve sits on had turned to dust and is not able to be reused. I'm assuming that the gasket is there for something - maybe like someone surmised to isolate the valve from so heat?

In any case its paper thin and doesn't actually seal anything. Anyone see a problem in replacing it with a thin layer of high temp gasket maker?