New lever sets (combination type) are frequently unplated, or only partially plated and I've also seen the fasteners chemically blacked..To protect the base metal either cadmium or dull chrome would do the job and look right for the period, with the latter being far superior in terms of corrosion resistance and longevity...Nickel as a surface finish had been replaced well before the war apart from dull nickel being the original finish on Lucas dynamo bodies...
There are platers still doing dull chrome. However, some try to achieve the finish by other means (blasting, satinising soaps etc. etc.) which in my experience produces a poor to hopeless result (believe me I've tried them)....
A good guide to whether a plater can produce the 'real deal' is what they offer in nickel plating...The correct nickel base for dull chrome is dull nickel which again, many don't do...Ian
