.../...what parts exactly were plated when leaving the factory.../...
Guess we do not have a "list" as such in the Tech Wiki. Hmm
Well, in general cast or pipe metal items were yellow cad plated.
Hose clamps (Norma and band types) were silver grey plated
In some positions the nicely yellow cad items were painted over (in black) when a sub unit was painted as a whole before or during assembly in Sindelfingen.
.../... stickers that were placed on items in the engine bay and what they looked like.../..
The stickers differed between models over time. In the Wiki you find those suitable for a US vehicle. In Europe the text was often in German or multi language. There are sticker kits you can buy, for instance fron VdH in Germany
/Hans in Sweden
.