[Lucien Nunes]

There may be two separate effects at work here. I have noticed a similar effect in the UK - moulded BS1363 cordsets often have plated pins while rewireable plugs have plain brass. I think some moulded plugs do not have solid brass pins, hence need plating, while the rewireables incorporate screw terminals so need to be solid brass.

But in Europe I think there's another reason. Schuko (CEE7/4) plugs, both rewireable and moulded, are invariably plated, and in consequence so are hybrid (CEE7/7) types that fit both Schuko (CEE7/3) and French (CEE7/5) sockets. Since the majority of moulded cables come with hybrid plugs, it follows they will be chromed as per the black plug in the pic. But rewireable French plugs are often just CEE7/6 as per the white plug in the pic, not hybrid, therefore not plated.

My theory is therefore that any plug that is hybrid, moulded or both will be plated. Rewireable non hybrid CEE7/6 plugs may be plain brass or plated, the plain brass likely to be of French or French-derived manufacture and the plated more commonly generic Far Eastern.