Scene in the end set in the future-SPOILER
If I do the math correctly, Billy's death scene was probably set around the late 1990's or early 2000's, since he was in his 70's or 80's. In the book, he died in 1976 and America was several different countries, but he was clearly an elderly man in this one
Interesting note: apparently, in 1972 they didn't know that hairstyles and glasses would change in the future and the audience look very early 1970's