Another interesting point,

I have an 1954 FED 1g and interlayer is black. I dont know if there is an nickel layer but at portholes , there is lack of chrome but deep black layer. Is there a chance for that camera about lack of nickel or nickel and chromium peeled off together ?
I will ask to a plater about the tones of nickel layer , may be I can order small samples if they consider me serious.