Where can we find suggestions in the story that the narrator is a pampered punk?T.C. Boyle calls his self a pampered punk when recalling growing up.
The opening paragraph of "Greasy Lake" offers the reader the first glimpse into this idea:
We were all dangerous characters then. We wore torn-up leather jackets, slouched around with toothpicks in our mouths, sniffed glue and ether and what somebody said was cocaine. When we wheeled our parents' whining station wagons out into the street we left a patch of rubber half a block long. We drank gin and grape juice, Tango, Thunderbird, and Bali Hai. We were nineteen. We were bad.
From this we see clearly that the narrator and his friends are trying to give the appearance they are bad. We have reference to the torn-up jackets, toothpicks in their mouths, and "elaborate poses" to suggest their lack of concern for anything.
Very little here, however, describes the actions or behaviors of "dangerous characters." Sniffing glue, "burning rubber" (in their parents' station wagons, no less), and drinking gin and juice hardly constitute the behavior of hardened, dangerous men. These are teenagers trying to "bad." The fact of the matter, however, is that they are not bad and, in fact, are merely rebelling from their parents and society in a very mild and tame manner. "Pampered punks" seems to be a pretty apt description!