Re: Several Unrelated Questions.

The marker on DRGW engines are known commonly as "radial lens classification lamps". Named for the curved fresnel lenses. There two lenses, a clear and a green lens. Depending on the maker of the lamp, there is either a rotating "blind" inside to blank off the light to the undesired lens or the lenses are mounted on a seperate collar that turns to display the proper color. As (to my knowledge) the DRGW seldom, if ever, ran sections requiring greeen flags (other than in DGO in the early 60's), I wonder if any markers ever showed "green" in service.
Originally they were kerosene lamps. Later they were electified. When some lamps were electrified, they lost thier chimney tops.
A few other roads used these lamps. I have one marked "L&N".
I think the stars on the smokeboxes were a personal touch added by the engineer back in the days of when locomotives were assigned to a specific engineer. I was common for engineers to add personal touches such as antlers to the headlights, lodge emblems, etc. My favorite was the lace curtains in the cab windows of the 227 as seen in a Fred Jukes photo. As there was not much (if any) heat resistant paint around then, I would guess the stars were applied with white lead.