Citation:
The first month of humbucker Les Paul goldtop production used black plastic parts (pickguard, pickup rings, switch surround), with black parts being in the serial number range "7 13xx" to "7 32xx".
All black plastic 1957 Les Paul Goldtops should have a dark back (if it doesn't, chances are someone stole the cream parts and replaced them with black parts). The black pickguard is basically a 5 layer b/w/b/w/b Les Paul Custom pickguard (but cut for two humbucking pickups). Within a month or two, PAF goldtops changed to cream plastic parts (cream part PAF goldtops not seen before serial number "7 3000"). Generally speaking black plastic part 1957 Les Paul goldtops are worth less than cream part 1957 goldtops though.