Richard Metzger's contribution to RAW Week at BOING BOING has a passage on Robert Anton Wilson's political philosophy:
"There's some confusion about what his political philosophy was like. Wilson is always claimed by the Libertarians because he was against people being arrested for victimless crimes, but the Libertarians won't tell you that RAW also was a strong proponent of the "basic income guarantee" which would make him more of a Socialist than Libertarian, of course, but really he was neither. He wasn't deluded by any political system is perhaps the best way to put it)."
It's true that Wilson favored a basic income guarantee, and later in life he also expressed support for government provided health care for all, something Metzger could have cited to help prove his case. And yes, he broke with mainstream libertarians in certain ways. (See the long interview with New Libertarian Notes, which goes into considerable detail on certain points.)
Still, it feels like a stretch to suggest there's something wrong with libertarians claiming RAW, or to say it's only because "he was against people being arrested for victimless crimes."
Explaining his vote for John Anderson in 1980, Wilson said, "Ideologically, of course, I should have voted for Ed Clark, the Libertarian Party candidate; but I am not that kind of Libertarian, really; I don't hate poor people."
"Ideologically, of course ... " The ILLUMINATUS! trilogy is filled with pages and pages of libertarian and anarchist propaganda. (Simon Moon, one of the main characters, is a left anarchist, but Hagbard Celine, arguably the most important viewpoint character, is a straightforward libertarian).
Wilson wrote many columns for New Libertarian Notes. He was a celebrity within the libertarian movement. When he ran for governor of California, his Guns & Dope Party platform was straightforwardly libertarian (excepting the surrealistic ostriches). For example, the platform called for voluntary taxation, as well as full gun and drug rights. He sometimes referred to himself as a "libertarian" in his writings.
I don't object if a progressive such as Metzger wants to claim RAW, but libertarians have as much right to him as anyone.
Footnote: This seems like a convenient time to recommend Metzger's excellent Dangerous Minds blog. The New Yorker just gave the blog a nice writeup.