I don't know if they're gold ...or brass...or whatever - and then just have a coat of lacquer over them to keep them from tarnishing...
Its just a marketing thing.../ I don't think it signifies anything specifically...a lot of the Browning models have had gold triggers for a long time..( I don't even know when it started )....you must be bored today, if that's what's on your mind ...??? geez....
and as a note...( since I worked for Peterbilt for 20 yrs.....I thought the Mack Bulldog was just lame...) ...
You probably already know that old truckers never die, they just get a new Peterbilt...!