I don't know if they ever said. I stopped reading the JSA around that time. I think that retcon was retcon'd away.

Just a guess here;
Jim "Spectre" Corrigan and Hal "Green Lantern" Jordan ???

Nope, neither of those two. (I'm not sure, but I think they were both in the 1966 JLA/JSA team-up, JLA #'s 46-47).

Definitely not. Both of them were in the 1963 (JLA #21-22) and 1971 (91-92) team-ups.

Superman and Superman?

--nah.
wyld

Nah is right.

Black Canary and Green Arrow?

No no no, sorry. You're wrong. They had both had, at those times, been secretly replaced by shape-shifting White Martians. And their leader was known as Adaseuq. He was sort of like Supes imp, Myz (I can't remember how to spell it), only this was a martian version.

Thinking out loud:

I can't quote JLA-JSA teamup rosters very easily, but I think we can rule out Flash (x2), Green Lantern (x2), Dr. Fate, Starman, Hawkman (x2?), J'onn, Wonder Woman, Superman, Batman, Atom, Aquaman (?).

How about Hawkgirl and Hawkwoman?

(I feel like we're trying too hard to make it two versions of the same character.)

--wyld

Here's a free hint; it's not two versions of the same character.

Not a bad guess! But they had appeared in at least one JLA/JSA team-up together, 1975 (JLA #123-124).