It's not an OE color, but may be a Porsche color from a later model year.
Back in 1980 I'd repainted my 73 2L to a similar but darker Anthracite Grey Metallic as a "Pavement Cammy" so as not to stand out as much as the Copper Metallic I had repainted it before in 76 - which looked like a metallic orange to the cops & CHP!
Click to view attachment ... after getting whacked in May 85 then sitting in my garage since, that one looks far better, but he doesn't have my hand painted pinstripes!