Continuity mistake: When Silent Bob is telling the Amy story in the diner, his cigarette mysteriously grows from barely above the filter to about half length, then it disappears from his hand entirely, and he draws a new one. (01:30:40)
Continuity mistake: During the hockey fight, number 12's helmet is off, then on, then off again. (01:17:00)
Continuity mistake: Towards the end where Silent Bob is in the diner, he finishes reading a comic book and they show him toss it on the table. However, in the very next shot from a different angle he has the comic book in his hand again and tosses it on the table once more. (01:25:15)
Continuity mistake: At the end, when the fan at the convention gives the last issue of Bluntman And Chronic to Banky to sign, Banky looks through the book with his pen in his left hand. It cuts away, and then back again, and the pen is in his right hand. (01:44:20)
Continuity mistake: During the dart scene, the customers who use the restrooms ignore the gender signs. (Most likely intentional, but worth a look). (00:14:20)
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