I remembered my first Luger. It's an Interarms Mauser which has strawed small parts. I did not know there was a type of finish called "strawed" at that time, but realized the trigger must be covered by a layer of "ugly" oxidation. So I took it off and sanded it with 800-grit sand paper with considerable amount of energy -- bare metal is silver. I sold it later on..... if I looked back, obviously the buyer had no idea of "strawed finish" either
Anyway, I confirm the color of trigger and thumb safety in bare metal form is silver.