You are wholly mistaken and arguing against a point the finest historians of firearm metallurgy are in complete agreement upon. You are also arguing against those of use who have done this for decades on our own guns, and not providing contrary empirical evidence.
I'm not "arguing against" you or anyone else. I am basing what I'm saying on a career spanning over 45 years in the metals industry. Not a letter from a historian you have tucked away somewhere, that you can't seem to find. Or some article you read once upon a time, somewhere out there in Cyberspace. You can believe and do whatever you want. It doesn't matter to me in the least. I'm not trying to convince you of anything.
I am simply telling you it is standard practice in the plating industry to flash plate steel with copper before applying Nickel, in any type of electro plating operation. I don't care if it involves motorcycle parts, car bumpers, medallions, or firearms.
The reason for this is as I stated. It allows for much better adhesion of the Nickel to the base metal it is being applied to. It also prevents any type of oxide, (rust), from forming underneath the Nickel. If it should be compromised or violated, by a scratch that penetrated through the thin Nickel plating itself. Without the copper base, flaking of the Nickel will occur much faster. And over a much broader area. The copper base is also much more conductive to the electro process involved in applying the Nickel. Which allows a much better, and more uniform thickness application of the Nickel itself. This is very critical when uniform buildup is required on closely fit parts. Like many that firearms are comprised of. Which is one of the main reasons Nickel plated firearms
should not be cleaned with any type of copper removing solvent like Ballistol or Hoppes. This is simply common sense.
I'm not saying or suggesting there are not Nickel plated firearms out there where this procedure has not been followed. Any process can be shortcut to save cost. Or else done improperly.
Is it possible for firearms, or anything else made of steel be Nickel plated without a flash copper base?.... YES. Will the results be of the same enduring quality?..... NO. If you talk to any respectable firearms refinisher in the trade today, like Ford's or Robar. They will tell you the exact same thing.