Part of Captain America's allure was that there was supposedly just one left. A total of four motorcycles were reportedly made for the movie – two each for Peter Fonda and Dennis Hopper's characters. One of those was crashed in the film's finale, and the three others were allegedly stolen prior to the premiere. Future Grizzly Adams star Dan Haggerty worked on the set as a mechanic and was given the wrecked cycle at the end of production. He restored it and sold Captain America years later. Memorabilia collector Michael Eisenberg was the last owner and put the bike up for this action.
A recent report from The Los Angeles Times found a possible issue with that story because Haggerty sold a different Captain America in 1996, and he claimed that motorcycle was the genuine article. To be clear, this wasn't the bike that just sold for $1.35 million. When asked, Haggerty told the newspaper that the original authentication was a "mistake", and the latest sale was for the real one.
The LA Times also spoke with Fonda to try to unravel things. He had previously authenticated the just-auctioned Captain America but now regrets it. At the time, he didn't know about the earlier sale. Fonda's not sure which one is real.
Unfortunately, really figuring things out might not be so easy. Like Eisenberg told The LA Times, "Dan Haggerty is the only guy who knows."