Stock Exhaust Gaskets w/Headers?

aren't "stock exhaust gaskets" tin embossed pieces? How would they ever seal a set of headers?
no, they're a sandwich of thick foil with what looks like asbestos (or similar) in the middle. they'll crush conforming to slight discrepances in the stock manifolds. unless i'm buying new headers i just use the stock gaskets with a smear of silicon each side. not had header leaks yet. also as the silicon squeezes out around the bolt threads it helps to stop them from backing out so win win.
neil.