The '60s Abbie Hoffman dropped by for lunch the other day, arriving unannounced in a plaid shirt and an attitude of cheerful complaint.

"How'd you get past the security guard, Abbie?" he was asked.

"Hey," said Hoffman, with the prideful air of a guy with a reputation, "You're talkin' to the author of 'Steal This Book.' "

Hoffman, 45, became well known, not to say notorious, in the 1960s for his politics, then spent seven years underground after he was arrested for selling cocaine. He surfaced in 1981, served a year of the three-year sentence he got in a plea bargain, and now lives in the Thousand Islands area of upstate New York. He is active on behalf of ecological concerns, often under his underground name of Barry Freed.

Interestingly, he was active in the ecology field under the name Freed before he went public, earning the commendation of Sen. Daniel Patrick Moynihan, with whom he posed as a bearded Freed.

This rather schizoid existence, in addition to providing Hoffman with a nervous breakdown while underground, has had its confusion above ground as well.

Abbie, a.k.a. Barry, refers to himself in the third person as either Abbie or Barry ("Abbie's got 34 speaking dates") and carries, in his wallet, identification in both names. (Barry has the fishing license, Abbie gets to drive.) Both Abbie and Barry are active in environmental fights, Abbie being the national spokesman for Save the River, Barry being the chairman of the Nuclear Waste Task Force.

Most important, it was revealed over lunch at the neighborhood sushi bar, both Barry and Abbie have their own personalities and quirks.

"Abbie speaks a lot louder, and swears and screams," said Abbie/Barry, who not for nothing was known as the 1960s' most outrageous Yippie. "Barry doesn't swear, he's more polite. Abbie, when he speaks, is more of a rebel. He talks about how the spirit of the '50s and '60s is battling for the '80s, and makes jokes about how he doesn't trust anyone under 30; about Reaganomics and El Salvador. It's hard for Barry to tell jokes. They've got a different kind of humor up there [in the Thousand Island area]. But he's able to get directly into the substance of issues without all the anecdotal stuff. Barry gets $200, $300 for speaking, and most of the time speaks for free. Abbie gets $3,500."

Also, it was learned, the two have distinct identities in the financial community.

"Abbie got turned down in New York City for a loan. Well, look, [it's] hard to establish credit when you're underground. Barry got an $8,000 personal line upstate with the Key Bank of New York. They said, 'We know you, we know you pay your bills.' "

If Abbie, who has never precisely been known to shun the spotlight, has a major gripe these days, aside from environmental issues, it is the press. They think of him only as an old hippie, he complains, though he's been an organizer, a civil rights activist for 22 years. They say he got preferential treatment with a short prison sentence for the cocaine deals, though two of his five co-defendents did no time at all. They say he lives, with lover Johanna Lawrenson, in a house of great splendor, in some wealth.

"A small town, mostly unemployed, and The Daily News makes it sound like the Hamptons, with 'rolling hills.' It doesn't have a hill in the whole town," he says. "The Times writes that it's the 'sunset' of the movement. I outdraw Gordon Liddy two to one. I had 5,000 at Stony Brook. Irving Howe in "The Decade That Failed" writes about Jerry Rubin in detail. Why can't he write about me? I was one of his students. It's that I don't fit into his equation of idealism, I didn't become disillusioned. I didn't become greedy. . . . Most of the '60s activists are still activists. They've moved to the country. Dave Dellinger is across from me, organizing against nuclear waste in Vermont. . . . "

The idea that he has grown rich is also, he says, incorrect. He gives away one third of his income to political causes. Check it with his accountant, he says. (It checks.) The most expensive piece of clothing he has are his boots, he says. He works, opposing the transport of nuclear waste, 12 and 14 hours.

"I consider myself an American dissenter," he says.

Which self?

"Abbie."

What about Barry?

"You have to ask him."

So what are you, Barry?

"A local citizen concerned about the community."