Jean Grey is in the car with her parents. It’s 1975, a screen title tells us.
She’s telepathically bickering over what plays on the car radio. Glen Campbell, or this other song.
Because Jean, even at that tender age, can see or HEAR the future. She was into Warren Zevon three years before he recorded “Werewolves of London.”
Movie Nation 
The copyright date on Werewolves Of London is 1975. WZ was performing it in live shows at that time, so it’s not as stupid as you think it is.
Wikipedia is your friend. It hit LP and was released as a single to RADIO STATIONS in Jan. of 1978.
That doesn’t negate the fact that WZ was performing it live since 1975.
Talking about the MOVIE where it plays on the RADIO. That’s what’s in the MOVIE. In “1975.” Which is WHAT I WROTE. I know you’re not adult enough to admit you’re wrong, but go here https://en.wikipedia.org/wiki/Werewolves_of_London.
Go troll somebody else with your deep insights into the Warren Zevon songbook, and your inability to comprehend writing in English, thus utterly missing the point.