Resurrecting this older thread with some background info for you. Abraxas #1 is actually a reprint of Walt's first comic, which was indeed called The Outsiders. The inside front cover of your magazine is a modified version of the original's back cover, which is where it's identified as The Outsiders. The first issue was published in 1971, the second in 1972. Abraxas #1 was published between the two issues. The original comics are much smaller than Abraxas, something like 6"x9".
Source: I have both comics, and I was also friends with the writer, Gerry Boudreau, who also did work for DC, Gold Key, and Warren in the 70s.
I also have a mimeographed promotional flyer Rickey Shanklin created for the magazine.