· Just some guy
67 coupe, 69 Sportsroof, 86 hatchback
I've seen that before. There exists gasket grades known as "rebuilder grade". Many are/were little more than cardboard. Many years ago I knew a guy at a high volume engine rebuilding company. A buddy needed some head gaskets and the guy hooked us up with an entire engine rebuild gasket kit for less than what a single head gasket would have cost my buddy. We used the head gaskets and they worked fine but the rest of the gaskets were of obvious laughably low quality and we threw them away. They were that same white fiber looking stuff as what remains of that old gasket. The gray FelPro-looking one you have put on should last you just fine.