Dale Gribble is the road worker near the beginning.Seeing Bill Foster in a field jacket and a gun in his pants, destroying the water main with an M72, is what pushed Dale over the edge and turned him into the conspiracy-crazed gun nut we know.
D-FENS is actually Teddy Duchamp.Given that both characters are insane, patriotic, and hot-headed, both look similar in appearance, it is entirely possibly that "Bill Foster" was a paranoia-induced alias. Given that Falling Down takes place in 1993 (with D-FENS being played by 48-year-old Michael Douglas) and Stand by Me takes place in 1959 (With Teddy being about 12), he would be exactly the right age from is previous adventures in Castle Rock. Regarding his ear, we know that plastic surgeons exist, and it could be possibly why he looks concerned when he finds out the mansion is owned by a plastic surgeon.
- Depends on whether you consider the original story, The Body, which has Teddy dying in a DUI car crash (he's the driver) in 1972, or the film, which has him as an ex-con doing odd jobs in Maine as an adult, to be canon. Either way, I think this is jossed.