I have a chapter in my book on the Elsinore Ghost, and while I don't believe that Cooper was the ghost, I don't think Cameron was lying. He was a do-gooder. He had been an LAPD officer in the 1950s and spent 15 years as an officer in the military. The FBI had previously vetted him in the mid-60's and he was cleared to be an informant.
In Jan 72, he was ousted as the National Director of the USPA by a 17-2 vote of their Board of Directors. He had found himself in hot water after making accusations that the U.S. Parachute Team were involved in illegal narcotics and were all drug users. The Board also voted to strip him of his ranking as an international skydiving judge. Doesn't seem like the type of individual who would go commit a felony by lying to the FBI.
I strongly disagree with your assertion that he was trying to promote his publication because he wouldn't have even been allowed to publicize it. The FBI would have directed him not to disseminate it lest it compromise the investigation into the tip. And again, how could him making up the story have benefited him? He was already the National Director of the USPA and the biggest swinging dick in the entire skydiving community. If anything, providing the tip would have hurt his stock. Skydiving in that era was full of outlaws. Doing something that brought a bunch of feds around to your DZ would have been massively frowned upon, especially for someone about to be ousted by the community for snitching.
I've tried like hell to find the early 72 issues of Sky Diver magazine to see if he actually promoted this story. There are no scanned versions online and the only ones for sale are part of a huge collection being sold as a lot. So there are no individual copies out there for purchase or viewing.
I don't think he was lying about the encounter, but I would not be surprised if he embellished the story a bit. The skeptic in me has alarm bells going off during the the Raleigh cigarettes part. That's just way too on the nose to be totally authentic.