Ok. I did a quick search and found this
http://kathyschrock.net/graffiti/coupe.htm
It says the guy in Frisco bought it from someone in Wichita. But a couple of things don't jive. It says the plates were missing. When the car was originally purchased from the film company the plates were still with it. The air cleaners were missing as this article says, but the rest of the car was there.
Something else that doesn't jive is what I first read about the car after it's sale from the movie company was it was owned by the same guy that has the 55, and both cars were running, driving cars that he, the owner, would take out on occasion.
OK...I've typed all that...then found this:
As sequels usually go, More American Graffiti was a flop (once again the marketing gurus got it wrong!), so Universal felt it was time to retire the old warhorse once and for all. The occasion was highlighted by a sealed-bid auction, won by Steve Fitch who had previously acquired rights to the movie's black '55 Chevy. A couple years later, after persistent offers by a young die-hard American Graffiti fan named Rick Figari, the car changed owners again. It turns out that ever since Figari as a boy of eight-years-old saw the movie, he had been infatuated with the coupe. When Fitch made it available for sale in 1985, the young man from San Francisco, California, had the dough. Figari was only 20 years old at the time, and his acquisition probably assured that the coupe would be preserved as the American Graffiti coupe for years to come. Among the first orders of business was to contract Roy Brizio's shop in South San Francisco to make the car roadworthy again.
Indeed, Figari spent the next few years actually driving the car, and it became a fixture in the Bay Area street rod scene. That is, until Figari, who owns and operates his own saloon in the city, concluded that the car's special historical and financial significance justified it as more than just a daily driver. And so, once again, the American Graffiti coupe was parked, this time in honor of its heritage.
The car currently is available for display at car shows and events across the nation. Figari maintains a website in its honor--www.milnerscoupe.com--and the car now is officially known as the Milner coupe. But everybody who is familiar with this bright yellow five-window highboy knows it as the American Graffiti coupe. After all, this is the hot rod that many of today's street rod enthusiasts cut their teeth on. Just ask Rick Figari, the owner of the most recognizable hot rod on the planet.