Visible crew/equipment: The cameraman is visible in the reflection of window while Holden is walking back to his car in the rain.
Visible crew/equipment: In the record store scene with Holden and Hooper talking about Holden's insecurities regarding Alyssa, Holden's (Ben Affleck) microphone is easily seen bulging in his shirt. (01:10:30)
Answer: I'm gonna be totally honest... I'm 99% sure there's no significance. In fact, I think it's just stained skin from all the smoking people do in the movie. Most people hold their cigarettes between their first two fingers. And most of the characters are depicted smoking throughout the film, which means they had to smoke a LOT during filming to maintain continuity. I used to get occasional orange (and sometimes yellow or light brown) stains on my fingers and hands when I smoked cigarettes. Especially if I smoked more than one in a short period of time and didn't wash me hands between them. So it's probably just smoking stains on the actor's fingers. In fact, I looked, and you see Banky holding a lit cigarette in his right hand and smoking during the story swapping scene you mentioned, with gives some direct evidence to my theory. (For reference, those stains can wash off with some good scrubbing).
TedStixon