I've never seen an old PAF cover that looked like that. Are those the DMC covers or RS? I've seen the RS turn black when exposed to moisture (sitting outside on a roof for several months), almost like they were carbon steel and had been dropped in a gun blueing tank. I kept a set of DMC's next my exercise bike for a few months wiping sweat on them every day, and while the oxidation came out great, I wasn't able to get the areas under the strings or the wear around the edges right without them being installed on a playable guitar. Sweat, grime, and time make old guitar parts look old. I have seen very few on hardware or finish relic jobs that were even halfway convincing in person. I know its not an option for a lot of people who either want the relic stuff or need to replace parts on old guitars, but the best way to age guitar parts is to play them for years
