not 100% sure
back in the 80's, they used nickel tuners, but chrome bridge, tail and pickup covers
the chrome parts age in a quite different tone, keeping the bluey silver shiny thing, even when rusted, while the aged nickel tuners look just like worn off gold parts
but Gibson annouces the '57 Goldtop Darkback as nickel hardware, so it probably is
not sure about the Yamano